User equipments and communication methods

Abstract

A method performed by a user equipment (UE) is described. The method includes receiving a PSSCH in a SL resource pool, the SL resource pool consisting of multiple RB sets and one or more intra-cell guard bands in frequency domain, and the PSSCH been allocated with a first number, N, of sub-channels; and determining Physical Sidelink Feedback Channel (PSFCH) resources for the PSSCH based on a second number, M, of sub-channels, wherein the M sub-channels are selected from the N sub-channels, and wherein all Physical Resource Blocks (PRBs) of each of the M sub-channels are contained within a single RB set.

Description

[DESCRIPTION][Title of Invention]USER EQUIPMENTS AND COMMUNICATION METHODS[Technical Field]

[0001] The present disclosure relates to a user equipment, and a communication method.[Background Art]

[0002] At present, as a radio access system and a radio network technology aimed for the fifth generation cellular system, technical investigation and standard development are being conducted, as extended standards of Long Term Evolution (LTE), on LTE-Advanced Pro (LTE-A Pro) and New Radio technology (NR) in The Third Generation Partnership Project (3GPP).

[0003] In the fifth generation cellular system, three services of enhanced Mobile BroadBand (eMBB) to achieve high-speed and large-volume transmission, UltraReliable and Low Latency Communication (URLLC) to achieve low-latency and high- reliability communication, and massive Machine Type Communication (mMTC) to allow connection of a large number of machine type devices such as Internet of Things (loT) have been demanded as assumed scenarios.

[0004] For example, wireless communication devices may communicate with one or more device. For sidelink communication, two communication devices can communicate with each other via PC5 interface. However, given the existing sidelink communication methods cannot directly applied to unlicensed spectrum, the flexibility and / or the efficiency of the whole sidelink communication system would be limited. As illustrated by this discussion, systems and methods according to the present invention, supporting sidelink communication over unlicensed spectrum, which may improve the communication flexibility and / or efficiency, would be beneficial.[Brief Description of the Drawings]

[0005] Figure 1 is a block diagram illustrating one configuration of one or more base stations and one or more user equipments (UEs) in which systems and methods for determination of frequency resources for a PSFCH occasion in a resource pool for SL transmissions may be implemented;

[0006] Figure 2 is a diagram illustrating one example 200 of a resource grid;

[0007] Figure 3 is a diagram illustrating one example 300 of common resource block grid, carrier configuration and BWP configuration by a UE 102 and a base station 160;

[0008] Figure 4 is a diagram illustrating one 400 example of CORESET configuration in a BWP by a UE 102 and a base station 160;

[0009] Figure 5 is a diagram illustrating one example 500 of interlaced transmission and reception in a BWP;

[0010] Figure 6 is a diagram illustrating one example 600 of a SL BWP and a resource pool within the SL BWP;

[0011] Figure 7 is a diagram illustrating one example 700 of a SL carrier with intracell guard band(s);

[0012] Figure 8 is a diagram illustrating one example 800 of sub-channel determination in a resource pool by a UE 102;

[0013] Figure 9 is a diagram illustrating another example 900 of sub-channel determination in a resource pool by a UE 102;

[0014] Figure 10 is a diagram illustrating one example 1000 of determining PSFCH occasions in time domain in a resource pool;

[0015] Figure 11 is a diagram illustrating one implementation of a method 1100 for determination of frequency resources for PSFCH transmission and reception per RB set in a resource pool by a UE 102;

[0016] Figure 12 illustrates various components that may be utilized in a UE;

[0017] Figure 13 illustrates various components that may be utilized in a base station;[Description of Embodiments]

[0018] A user equipment (UE) is described. The UE includes reception unit configure to receive a PSSCH in a SL resource pool, the SL resource pool consisting of multiple RB sets and one or more intra-cell guard bands in frequency domain, and the PSSCH been allocated with a first number, N, of sub-channels; and control circuitry configured to determine Physical Sidelink Feedback Channel (PSFCH) resources for the PSSCH based on a second number, M, of sub-channels, wherein the M sub-channels are selected from the N sub-channels, and wherein all Physical Resource Blocks (PRBs) of each of the M sub-channels are contained within a single RB set.

[0019] A communication method performed by a user equipment (UE) is described. The method includes receiving a PSSCH in a SL resource pool, the SL resource pool consisting of multiple RB sets and one or more intra-cell guard bands in frequency domain, and the PSSCH been allocated with a first number, N, of sub-channels; and determining Physical Sidelink Feedback Channel (PSFCH) resources for the PSSCH based on a second number, M, of sub-channels, wherein the M sub-channels are selected from the N sub-channels, and wherein all Physical Resource Blocks (PRBs) of each of the M sub-channels are contained within a single RB set.

[0020] 3GPP Long Term Evolution (LTE) is the name given to a project to improve the Universal Mobile Telecommunications System (UMTS) mobile phone or device standard to cope with future requirements. In one aspect, UMTS has been modified to provide support and specification for the Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN). 3 GPP NR (New Radio) is the name given to a project to improve the LTE mobile phone or device standard to cope with future requirements. In one aspect, LTE has been modified to provide support and specification (TS 38.331, 38.321, 38.300, 37.340, 38.211, 38.212, 38.213, 38.214, etc.) for the New Radio Access (NR) and Next generation - Radio Access Network (NG-RAN).

[0021] At least some aspects of the systems and methods disclosed herein may be described in relation to the 3GPP LTE, LTE-Advanced (LTE-A), LTE-Advanced Pro, New Radio Access (NR), and other 3G / 4G / 5G standards (e.g., 3 GPP Releases 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, and / or 18, and / or Narrow Band-Internet of Things (NB-IoT)). However, the scope of the present disclosure should not be limited in this regard. At least some aspects of the systems and methods disclosed herein may be utilized in other types of wireless communication systems.

[0022] A wireless communication device may be an electronic device used to communicate voice and / or data to a base station, which in turn may communicate with a network of devices (e.g., public switched telephone network (PSTN), the Internet, etc.). In describing systems and methods herein, a wireless communication device may alternatively be referred to as a mobile station, a UE (User Equipment), an access terminal, a subscriber station, a mobile terminal, a remote station, a user terminal, a terminal, a subscriber unit, a mobile device, a relay node, etc. Examples of wireless communication devices include cellular phones, smart phones, personal digitalassistants (PDAs), laptop computers, netbooks, e-readers, wireless modems, industrial wireless sensors, video surveillance, wearables, vehicles, roadside units, infrastructure devices, etc. In 3 GPP specifications, a wireless communication device is typically referred to as a UE. However, as the scope of the present disclosure should not be limited to the 3GPP standards, the terms “UE” and “wireless communication device” may be used interchangeably herein to mean the more general term “wireless communication device”.

[0023] In 3GPP specifications, a base station is typically referred to as a gNB, a Node B, an eNB, a home enhanced or evolved Node B (HeNB) or some other similar terminology. As the scope of the disclosure should not be limited to 3GPP standards, the terms “base station,”, “gNB”, “Node B,” “eNB,” and “HeNB” may be used interchangeably herein to mean the more general term “base station.” Furthermore, one example of a “base station” is an access point. An access point may be an electronic device that provides access to a network (e.g., Local Area Network (LAN), the Internet, etc.) for wireless communication devices. The term “communication device” may be used to denote both a wireless communication device and / or a base station.

[0024] It should be noted that as used herein, a “cell” may be any communication channel that is specified by standardization or regulatory bodies to be used for International Mobile Telecommunications-Advanced (IMT-Advanced), IMT-2020 (5G) and all of it or a subset of it may be adopted by 3GPP as licensed bands (e.g., frequency bands) to be used for communication between a base station and a UE. It should also be noted that in NR, NG-RAN, E-UTRA and E-UTRAN overall description, as used herein, a “cell” may be defined as “combination of downlink and optionally uplink resources.” The linking between the carrier frequency of the downlink resources and the carrier frequency of the uplink resources may be indicated in the system information transmitted on the downlink resources.

[0025] “Configured cells” are those cells of which the UE is aware and is allowed by a base station to transmit or receive information. “Configured cell(s)” may be serving cell(s). The UE may receive system information and perform the required measurements on configured cells. “Configured cell(s)” for a radio connection may consist of a primary cell and / or no, one, or more secondary cell(s). “Activated cells” are those configured cells on which the UE is transmitting and receiving. That is, activated cells are those cells for which the UE monitors the physical downlink controlchannel (PDCCH) and in the case of a downlink transmission, those cells for which the UE decodes a physical downlink shared channel (PDSCH). “Deactivated cells” are those configured cells that the UE is not monitoring the transmission PDCCH. It should be noted that a “cell” may be described in terms of differing dimensions. For example, a “cell” may have temporal, spatial (e.g., geographical) and frequency characteristics.

[0026] The base stations may be connected by the NG interface to the 5G - core network (5G-CN). 5G-CN maybe called as to NextGen core (NGC), or 5G core (5GC). The base stations may also be connected by the SI interface to the evolved packet core (EPC). For instance, the base stations may be connected to a NextGen (NG) mobility management function by the NG-2 interface and to the NG core User Plane (UP) functions by the NG-3 interface. The NG interface supports a many-to-many relation between NG mobility management functions, NG core UP functions and the base stations. The NG-2 interface is the NG interface for the control plane and the NG-3 interface is the NG interface for the user plane. For instance, for EPC connection, the base stations may be connected to a mobility management entity (MME) by the S 1 - MME interface and to the serving gateway (S-GW) by the Sl-U interface. The SI interface supports a many-to-many relation between MMEs, serving gateways and the base stations. The SI -MME interface is the SI interface for the control plane and the Sl-U interface is the S 1 interface for the user plane. The Uu interface is a radio interface between the UE and the base station for the radio protocol.

[0027] The radio protocol architecture may include the user plane and the control plane. The user plane protocol stack may include packet data convergence protocol (PDCP), radio link control (RLC), medium access control (MAC) and physical (PHY) layers. A DRB (Data Radio Bearer) is a radio bearer that carries user data (as opposed to control plane signaling). For example, a DRB may be mapped to the user plane protocol stack. The PDCP, RLC, MAC and PHY sublayers (terminated at the base station 460a on the network) may perform functions (e.g., header compression, ciphering, scheduling, ARQ and HARQ) for the user plane. PDCP entities are located in the PDCP sublayer. RLC entities may be located in the RLC sublayer. MAC entities may be located in the MAC sublayer. The PHY entities may be located in the PHY sublayer.

[0028] The control plane may include a control plane protocol stack. The PDCP sublayer (terminated in base station on the network side) may perform functions (e.g.,ciphering and integrity protection) for the control plane. The RLC and MAC sublayers (terminated in base station on the network side) may perform the same functions as for the user plane. The Radio Resource Control (RRC) (terminated in base station on the network side) may perform the following functions. The RRC may perform broadcast functions, paging, RRC connection management, radio bearer (RB) control, mobility functions, UE measurement reporting and control. The Non-Access Stratum (NAS) control protocol (terminated in MME on the network side) may perform, among other things, evolved packet system (EPS) bearer management, authentication, evolved packet system connection management (ECM)-IDLE mobility handling, paging origination in ECM-IDLE and security control.

[0029] Signaling Radio Bearers (SRBs) are Radio Bearers (RB) that may be used only for the transmission of RRC and NAS messages. Three SRBs may be defined. SRBO may be used for RRC messages using the common control channel (CCCH) logical channel. SRB1 may be used for RRC messages (which may include a piggybacked NAS message) as well as for NAS messages prior to the establishment of SRB2, all using the dedicated control channel (DCCH) logical channel. SRB2 may be used for RRC messages which include logged measurement information as well as for NAS messages, all using the DCCH logical channel. SRB2 has a lower priority than SRB1 and maybe configured by a network (e.g., base station) after security activation. A broadcast control channel (BCCH) logical channel may be used for broadcasting system information. Some of BCCH logical channel may convey system information which may be sent from the network to the UE via BCH (Broadcast Channel) transport channel. BCH may be sent on a physical broadcast channel (PBCH). Some of BCCH logical channel may convey system information which may be sent from the network to the UE via DL-SCH (Downlink Shared Channel) transport channel. Paging may be provided by using paging control channel (PCCH) logical channel.

[0030] System information may be divided into the MasterlnformationBlock (MIB) and a number of SystemlnformationBlocks (SIBs).

[0031] The UE may receive one or more RRC messages from the base station to obtain RRC configurations or parameters. The RRC layer of the UE may configure RRC layer and / or lower layers (e.g., PHY layer, MAC layer, RLC layer, PDCP layer) of the UE according to the RRC configurations or parameters which may be configured by the RRC messages, broadcasted system information, and so on. The base stationmay transmit one or more RRC messages to the UE to cause the UE to configure RRC layer and / or lower layers of the UE according to the RRC configurations or parameters which may be configured by the RRC messages, broadcasted system information, and so on.

[0032] The size of various fields in the time domain is expressed in time units and Nf=4096. The constantWhere

[0033] Multiple OFDM numerologies are supported as given by Table 4.2-1 of [TS 38.211] where μ and the cyclic prefix for a bandwidth part are obtained from the higher- layer parameter subcarrierSpacing and cyclicPrefix, respectively.

[0034] The size of various fields in the time domain may be expressed as a number of time units Tc=1 / (15000x2048) seconds. Downlink and uplink transmissions are organized into frames with Tf=(ΔfmaxNf / 100) · Tc= 10ms duration, each consisting of ten subframes of Tsf= (ΔfmaxNf / 1000) · Tc= 1ms duration. The number of consecutive OFDM symbols per subframe is Each frame is divided into two equally-sized half-frames of five subframes each with half-frame 0 consisting of subframes 0 -4 and halfframe 1 consisting of subframes 5 - 9.

[0035] For subcarrier spacing (SCS) configuration μ, slots are numberedin increasing order within a subframe andin increasing order within a frame. is the number ofslots per subframe for subcarrier spacing configuration μ. There are consecutiveOFDM symbols in a slot where depends on the cyclic prefix as given by Tables4.3.2-1 and 4.3.2-2 of [TS 38.211]. The start of slotin a subframe is aligned in time with the start of OFDM symbol in the same subframe. Subcarrier spacingrefers to a spacing (or frequency bandwidth) between two consecutive subcarriers in the frequency domain. For example, the subcarrier spacing can be set to 15kHz (i.e., μ=0), 30kHz (i.e. μ=1), 60kHz (i.e. μ=2), 120kHz (i.e. μ=3), or 240kHz (i.e. μ=4). A resource block is defined as a number of consecutive subcarriers (e.g., 12) in the frequency domain. For a carrier with different frequency, the applicable subcarrier may be different. For example, for a carrier in a frequency rang 1, a subcarrier spacing onlyamong a set of {15kHz, 30kHz, 60kHz} is applicable. For a carrier in a frequency rang 2, a subcarrier spacing only among a set of {60kHz, 120kHz, 240kHz} is applicable. The base station may not configure an inapplicable subcarrier spacing for a carrier.

[0036] OFDM symbols in a slot can be classified as 'downlink', 'flexible', or 'uplink'. Signaling of slot formats is described in subclause 11.1 of [TS 38.213],

[0037] In a slot in a downlink frame, the UE may assume that downlink transmissions only occur in 'downlink' or 'flexible' symbols. In a slot in an uplink frame, the UE may only transmit in 'uplink' or 'flexible' symbols.

[0038] Various examples of the systems and methods disclosed herein are now described with reference to the Figures, where like reference numbers may indicate functionally similar elements. The systems and methods as generally described and illustrated in the Figures herein could be arranged and designed in a wide variety of different implementations. Thus, the following more detailed description of several implementations, as represented in the Figures, is not intended to limit scope, as claimed, but is merely representative of the systems and methods.

[0039] Figure 1 is a block diagram illustrating one configuration of one or more base stations 160 (e.g., eNB, gNB) and one or more user equipments (UEs) 102 in which systems and methods for determination of frequency resources for a PSFCH occasion in a resource pool for SL transmissions may be implemented. The one or more UEs 102 may communicate with one or more base stations 160 using one or more antennas 122a-n. For example, a UE 102 transmits electromagnetic signals to the base station 160 and receives electromagnetic signals from the base station 160 using the one or more antennas 122a-n. The base station 160 communicates with the UE 102 using one or more antennas 180a-n. Additionally, one or more UEs 102 may communicate with one or more UEs 102 using one or more antennas 122a-n. For example, aUE 102 transmits electromagnetic signals to another UE(s) 102 and receives electromagnetic signals from another UE(s) 102 using the one or more antennas 122a- n. That is, one or more UEs communicate with each other via sidelink communication.

[0040] The UEs 102 may directly communicate with each other by using the sidelink communication. For illustration, UE(s) 102 capable of sidelink communication include a UE 1 A, a UE 1B and a UE 1 C. The UE 1A may be located within the coverage of the base station 160. The UE IB and the UE 1C may be located outside the coverage of the base station 160. The UE 1A and the base station 160 may communicate witheach other via downlink and uplink communication. In addition, the UE 1 A and the UE IB may directly communicate with each other via sidelink communication. In addition, the UE IB and the UE 1C may directly communicate with each other via side link communication.

[0041] It should be noted that in some configurations, one or more of the UEs 102 described herein may be implemented in a single device. For example, multiple UEs 102 may be combined into a single device in some implementations. Additionally or alternatively, in some configurations, one or more of the base stations 160 described herein maybe implemented in a single device. For example, multiple base stations 160 may be combined into a single device in some implementations. In the context of Figure 1, for instance, a single device may include one or more UEs 102 in accordance with the systems and methods described herein. Additionally or alternatively, one or more base stations 160 in accordance with the systems and methods described herein may be implemented as a single device or multiple devices.

[0042] The UE 102 and the base station 160 may use one or more channels 119, 121 to communicate with each other. For example, a UE 102 may transmit information or data to the base station 160 using one or more uplink (UL) channels 121 and signals. Examples of uplink channels 121 include a physical uplink control channel (PUCCH) and a physical uplink shared channel (PUSCH), etc. Examples of uplink signals include a demodulation reference signal (DMRS) and a sounding reference signal (SRS), etc. The one or more base stations 160 may also transmit information or data to the one or more UEs 102 using one or more downlink (DL) channels 119 and signals, for instance. Examples of downlink channels 119 include a PDCCH, a PDSCH, etc. APDCCH can be used to schedule DL transmissions on PDSCH and UL transmissions on PUSCH, where the Downlink Control Information (DCI) on PDCCH includes downlink assignment and uplink scheduling grants. APDCCH can be also used for scheduling of sidelink transmissions on PSCCH and PSSCH in one cell, where the Downlink Control Information (DCI) on PDCCH includes sidelink scheduling grants. The PDCCH is used for transmitting Downlink Control Information (DCI) in a case of downlink radio communication (radio communication from the base station to the UE). Here, one or more DCIs (may be referred to as DCI formats) are defined for transmission of downlink control information. Information bits are mapped to one or more fields defined in a DCI format. Examples of downlink signals include a primarysynchronization signal (PSS), a secondary synchronization signal (SSS), a cell-specific reference signal (CRS), a non-zero power channel state information reference signal (NZP CSI-RS), and a zero-power channel state information reference signal (ZP CSI- RS), etc. Other kinds of channels or signals may be used.

[0043] For the UE(s) 102 capable of sidelink communication, the UEs 102 may use one or more sidelink channels 123 to communicate with each other. For example, a UE 102 may transmit information or data to another UE 102 using one or more side link (SL) channels 123 and signals. Examples of sidelink channels 123 include a physical sidelink control channel (PSCCH), a physical sidelink shared channel (PSSCH), a physical sidelink feedback channel (PSFCH), and a physical sidelink broadcast channel (PSBCH). Examples of sidelink signals include a demodulation reference signal (DMRS), a phase-tracking reference signal (PT-RS), a channel-state information reference signal (CSI-RS), a sidelink primary synchronization signal (S-PSS), and a sidelink secondary synchronization signal (S-SSS).

[0044] Each of the one or more UEs 102 may include one or more transceivers 118, one or more demodulators 114, one or more decoders 108, one or more encoders 150, one or more modulators 154, one or more data buffers 104 and one or more UE operations modules 124. For example, one or more reception and / or transmission paths may be implemented in the UE 102. For convenience, only a single transceiver 118, decoder 108, demodulator 114, encoder 150 and modulator 154 are illustrated in the UE 102, though multiple parallel elements (e.g., transceivers 118, decoders 108, demodulators 114, encoders 150 and modulators 154) may be implemented.

[0045] The transceiver 118 may include one or more receivers (reception units) 120 and one or more transmitters (transmission units) 158. The one or more receivers 120 may receive signals (e.g., downlink channels, downlink signals, sidelink channels, side link signals) from the base station 160 or from another UE 102 using one or more antennas 122a-n. For example, the receiver 120 may receive and downconvert signals to produce one or more received signals 116. The one or more received signals 116 may be provided to a demodulator 114. The one or more transmitters 158 may transmit signals (e.g., uplink channels, uplink signals, sidelink channels, sidelink signals) to the base station 160 or to another UE 102 using one or more antennas 122a-n. For example, the one or more transmitters 158 may upconvert and transmit one or more modulated signals 156.

[0046] The demodulator 114 may demodulate the one or more received signals 116 to produce one or more demodulated signals 112. The one or more demodulated signals 112 may be provided to the decoder 108. The UE 102 may use the decoder 108 to decode signals. The decoder 108 may produce one or more decoded signals 106, 110. For example, a first UE-decoded signal 106 may comprise received payload data, which may be stored in a data buffer 104. A second UE-decoded signal 110 may comprise overhead data and / or control data. For example, the second UE-decoded signal 110 may provide data that may be used by the UE operations module 124 to perform one or more operations.

[0047] As used herein, the term “module” may mean that a particular element or component may be implemented in hardware, software or a combination of hardware and software. However, it should be noted that any element denoted as a “module” herein may alternatively be implemented in hardware. For example, the UE operations module 124 may be implemented in hardware, software or a combination of both.

[0048] In general, the UE operations module 124 may enable the UE 102 to communicate with the one or more base stations 160. For a UE capable of sidelink communication, the UE operations module 124 may enable the UE 102 to communicate with the one or more other UE. The UE operations module 124 may include a UE RRC information configuration module 126. For a UE capable of sidelink communication, the UE operations module 124 may include a UE sidelink (SL) control module (unit) 128. In some implementations, the UE operations module 124 may include physical (PHY) entities, Medium Access Control (MAC) entities, Radio Link Control (RLC) entities, packet data convergence protocol (PDCP) entities, and a Radio Resource Control (RRC) entity. For example, the UE RRC information configuration module 126 may process RRC parameter for random access configurations, initial UL BWP configuration, maximum bandwidth the UE can support, and cell specific PUCCH resource configuration(s).

[0049] For a UE capable of sidelink transmission, the UE RRC information configuration module 126 may process parameters included in the (pre-)configuration(s) related to sidelink communications. The UE RRC information configuration module 126 may include a memory unit to store the (pre-)configuration(s) related to sidelink communications. For example, the UE RRC information configuration module 126 may, based on the parameters, determine a SL BWP, one ormore resource pools within the SL BWP in frequency domain and time domain for SL communications. The UE RRC information configuration module 126 may provide information related to SL BWP configuration and resource pool configuration to the UE SL control module 128. The UE SL control module 128 may set the SL BWP configuration and the resource pool configuration.

[0050] The UE SL control module 128 may determine the frequency resources, the time resources, the code resources, and / or numerologies for transmission or reception of the PSCCH, the PSSCH, S-SS / PSBCH and / or the PSFCH. The frequency resources for transmission or reception of the PSCCH, the PSSCH and the PSFCH include information related to assigned sub-channel(s) (or interlace(s)) and RB set(s).

[0051] The UE operations module 124 may provide information 148 to the one or more receivers 120. For example, the UE operations module 124 may inform the receiver(s) 120 when or when not to receive transmissions based on the Radio Resource Control (RRC) message (e.g., broadcasted system information, RRC reconfiguration message), MAC control element, SCI (Sidelink Control Information) and / or the DCI (Downlink Control Information). The UE operations module 124 may provide information 148, including the PDCCH monitoring occasions, DCI format size, PSCCH monitoring occasions and SCI format size, to the one or more receivers 120. The UE operation module 124 may inform the receiver(s) 120 when or where to receive / monitor the PDCCH candidate for DCI formats and / or the PSCCH candidate for SCI formats. DCI formats can be used at least for scheduling of SL transmission(s) (PSCCH and / or PSSCH transmission(s)) in one cell and / or for scheduling of PUSCH and / or PDSCH in one cell.

[0052] The UE operations module 124 may provide information 138 to the demodulator 114. For example, the UE operations module 124 may inform the demodulator 114 of a modulation pattern anticipated for transmissions from the base station 160.

[0053] The UE operations module 124 may provide information 136 to the decoder 108. For example, the UE operations module 124 may inform the decoder 108 of an anticipated encoding for transmissions from the base station 160. For example, the UE operations module 124 may inform the decoder 108 of an anticipated PDCCH candidate encoding with which DCI size for transmissions from the base station 160. The UEoperations module 124 may inform the decoder 108 of an anticipated PSCCH candidate encoding with which SCI size for transmissions from another UE 102.

[0054] The UE operations module 124 may provide information 142 to the encoder 150. The information 142 may include data to be encoded and / or instructions for encoding. For example, the UE operations module 124 may instruct the encoder 150 to encode transmission data 146 and / or other information 142.

[0055] The encoder 150 may encode transmission data 146 and / or other information 142 provided by the UE operations module 124. For example, encoding the data 146 and / or other information 142 may involve error detection and / or correction coding, mapping data to space, time and / or frequency resources for transmission, multiplexing, etc. The encoder 150 may provide encoded data 152 to the modulator 154.

[0056] The UE operations module 124 may provide information 144 to the modulator 154. For example, the UE operations module 124 may inform the modulator 154 of a modulation type (e.g., constellation mapping) to be used for transmissions to the base station 160. The modulator 154 may modulate the encoded data 152 to provide one or more modulated signals 156 to the one or more transmitters 158.

[0057] The UE operations module 124 may provide information 140 to the one or more transmitters 158. This information 140 may include instructions for the one or more transmitters 158. For example, the UE operations module 124 may instruct the one or more transmitters 158 when to transmit a signal to the base station 160 or another UE 102. The one or more transmitters 158 may upconvert and transmit the modulated signal(s) 156 to one or more base stations 160 or another one or more UEs 102.

[0058] The base station 160 may include one or more transceivers 176, one or more demodulators 172, one or more decoders 166, one or more encoders 109, one or more modulators 113, one or more data buffers 162 and one or more base station operations modules 182. For example, one or more reception and / or transmission paths may be implemented in a base station 160. For convenience, only a single transceiver 176, decoder 166, demodulator 172, encoder 109 and modulator 113 are illustrated in the base station 160, though multiple parallel elements (e.g., transceivers 176, decoders 166, demodulators 172, encoders 109 and modulators 113) may be implemented.

[0059] The transceiver 176 may include one or more receivers (reception units) 178 and one or more transmitters (transmission units) 117. The one or more receivers 178 may receive signals (e.g., uplink channels, uplink signals) from the UE 102 using oneor more antennas 180a-n. For example, the receiver 178 may receive and downconvert signals to produce one or more received signals 174. The one or more received signals 174 may be provided to a demodulator 172. The one or more transmitters 117 may transmit signals (e.g., downlink channels, downlink signals) to the UE 102 using one or more antennas 180a-n. For example, the one or more transmitters 117 may upconvert and transmit one or more modulated signals 115.

[0060] The demodulator 172 may demodulate the one or more received signals 174 to produce one or more demodulated signals 170. The one or more demodulated signals 170 maybe provided to the decoder 166. The base station 160 may use the decoder 166 to decode signals. The decoder 166 may produce one or more decoded signals 164, 168. For example, a first base station-decoded signal 164 may comprise received payload data, which may be stored in a data buffer 162. A second base station-decoded signal 168 may comprise overhead data and / or control data. For example, the second base station-decoded signal 168 may provide data (e.g., PUSCH transmission data) that may be used by the base station operations module 182 to perform one or more operations.

[0061] In general, the base station operations module 182 may enable the base station 160 to communicate with the one or more UEs 102. For a base station capable of sidelink communication, the UE operations module 124 may enable the base station 160 to communicate with the one or more UEs 102 capable of sidelink communication. The base station operations module 182 may include a base station RRC information configuration module 194. For a base station capable of sidelink communication, the base station operations module 182 may include a base station sidelink (SL) control module 196 (or a base station SL processing module 196). The base station operations module 182 may include PHY entities, MAC entities, RLC entities, PDCP entities, and an RRC entity.

[0062] For a base station capable of sidelink transmission, the base station SL control module 196 may determine, for respective UE, the time and frequency resources for scheduling PSCCH and PSSCH and input the information to the base station RRC information configuration module 194.

[0063] The base station operations module 182 may provide the benefit of performing PDCCH candidate search and monitoring efficiently. The base station operations module 182 may provide information 190 to the one or more receivers 178. For example, the base station operations module 182 may inform the receiver(s) 178when or when not to receive transmissions based on the RRC message (e.g., broadcasted system information, RRC reconfiguration message), MAC control element, and / or the DCI (Downlink Control Information).

[0064] The base station operations module 182 may provide information 188 to the demodulator 172. For example, the base station operations module 182 may inform the demodulator 172 of a modulation pattern anticipated for transmissions from the UE(s) 102.

[0065] The base station operations module 182 may provide information 186 to the decoder 166. For example, the base station operations module 182 may inform the decoder 166 of an anticipated encoding for transmissions from the UE(s) 102.

[0066] The base station operations module 182 may provide information 101 to the encoder 109. The information 101 may include data to be encoded and / or instructions for encoding. For example, the base station operations module 182 may instruct the encoder 109 to encode transmission data 105 and / or other information 101.

[0067] In general, the base station operations module 182 may enable the base station 160 to communicate with one or more network nodes (e.g., a NG mobility management function, a NG core UP functions, a mobility management entity (MME), serving gateway (S-GW), gNBs). The base station operations module 182 may also generate a RRC reconfiguration message to be signaled to the UE 102.

[0068] The encoder 109 may encode transmission data 105 and / or other information 101 provided by the base station operations module 182. For example, encoding the data 105 and / or other information 101 may involve error detection and / or correction coding, mapping data to space, time and / or frequency resources for transmission, multiplexing, etc. The encoder 109 may provide encoded data 111 to the modulator 113. The transmission data 105 may include network data to be relayed to the UE 102.

[0069] The base station operations module 182 may provide information 103 to the modulator 113. This information 103 may include instructions for the modulator 113. For example, the base station operations module 182 may inform the modulator 113 of a modulation type (e.g., constellation mapping) to be used for transmissions to the UE(s) 102. The modulator 113 may modulate the encoded data 111 to provide one or more modulated signals 115 to the one or more transmitters 117.

[0070] The base station operations module 182 may provide information 192 to the one or more transmiters 117. This information 192 may include instructions for the one or more transmitters 117. For example, the base station operations module 182 may instruct the one or more transmitters 117 when to (or when not to) transmit a signal to the UE(s) 102. The base station operations module 182 may provide information 192, including the PDCCH monitoring occasions and DCI format size, to the one or more transmitters 117. The base station operation module 182 may inform the transmitter(s) 117 when or where to transmit the PDCCH candidate for DCI formats with which DCI size. The one or more transmitters 117 may upconvert and transmit the modulated signal(s) 115 to one or more UEs 102.

[0071] It should be noted that one or more of the elements or parts thereof included in the base station(s) 160 and LTE(s) 102 may be implemented in hardware. F or example, one or more of these elements or parts thereof may be implemented as a chip, circuitry or hardware components, etc. It should also be noted that one or more of the functions or methods described herein may be implemented in and / or performed using hardware. For example, one or more of the methods described herein may be implemented in and / or realized using a chipset, an application-specific integrated circuit (ASIC), a large-scale integrated circuit (LSI) or integrated circuit, etc.

[0072] A base station may generate a RRC message including the one or more R RC parameters and may transmit the RRC message to a UE. A UE may receive, from a base station, a RRC message including one or more RRC parameters. In the present disclosure, the terms ‘RRC parameter(s)’, ‘RRC information element(s)’, ‘higher layer parameter(s)’ can be used interchangeably. In the present disclosure, higher layer may refer to a layer upper than the physical layer (i.e., Layer 1), for example, MAC layer, RLC layer, PDCP layer, SDAP layer, RRC layer, and / or application layer.

[0073] A RRC parameter may further include one or more RRC parameter(s). In the present disclosure, a RRC message may include system information, a RRC message may include one or more RRC parameters. A RRC message may be sent on a broadcast control channel (BCCH) logical channel, a common control channel (CCCH) logical channel or a dedicated control channel (DCCH) logical channel.

[0074] In the present disclosure, a description “a UE is configured with or is provided a parameter” also implies the description “the UE may receive, from the base station, an RRC message (or information) which includes the parameter”. Likewise, thedescription “a base station configures the UE with or provides the UE the parameter” also implies the description “the base station may transmit, to the UE, an RRC message (or information) which includes the parameter”.

[0075] Figure 2 is a diagram illustrating one example of a resource grid 200.

[0076] For each numerology (i.e., for each SCS u) and carrier, a resource grid of Ngrid,xsize,μNscRBsubcarriers and Nsymbsubframe,μOFDM symbols is defined, starting at common resource block Ngridstart,μindicated by higher layer signaling. There is one set of resource grids per transmission direction (uplink or downlink) with the subscript x set to DL and UL for downlink and uplink, respectively. There is one resource grid for a given antenna port p, subcarrier spacing configuration μ, and the transmission direction (downlink or uplink). When there is no risk for confusion, the subscript x may be dropped.

[0077] In the Figure 2, the resource gird 200 includes the Ngrid,xsize,μNscRB(202) subcarriers in the frequency domain and includes Nsymbsubframe,μ(204) symbols in the time domain. In the Figure 2, as an example for illustration, the subcarrier spacing configuration μ is set to 0. That is, in the Figure 2, the number of consecutive OFDM symbols Nsymbsubframe,μ(204) per subframe is equal to 14.

[0078] The carrier bandwidth Ngridsize,μ(Ngrid,xsize,μ) for subcarrier spacing configuration μ is given by the higher-layer (RRC) parameter carrierBandwidth in the SCS-SpecificCarrier IE. The starting position Ngridstart,μfor subcarrier spacing configuration μ is given by the higher-layer parameter offsetToCarrier in the SCS- SpecificCarrier IE. The frequency location of a subcarrier refers to the center frequency of that subcarrier.

[0079] In the Figure 2, for example, a value of offset is provided by the higher- layer parameter offsetToCarrier. That is, k = 12xoffset is the lowest usable subcarrier on this carrier.

[0080] Each element in the resource grid for antenna port p and subcarrier spacing configuration μ is called a resource element and is uniquely identified by (k,l)p,μwhere k is the index in the frequency domain and I refers to the symbols position in the time domain relative to same reference point. The resource element consists of one subcarrier during one OFDM symbol.

[0081] A resource block is defined as NscRB=12 consecutive subcarriers in the frequency domain. As shown in the Figure 2, a resource block 206 includes 12consecutive subcarriers in the frequency domain. Resource block can be classified as common resource block (CRB) and physical resource block (PRB).

[0082] Common resource blocks are numbered from 0 and upwards in the frequency domain for subcarrier spacing configuration μ. The center of subcarrier 0 of common resource block with index 0 (i.e. CRB0) for subcarrier spacing configuration μ coincides with point A. The relation between the common resource block number in the frequency domain and resource element (k, I) for subcarrier spacing configuration μ is given by Formula (1) nCRBμ=floor(k / NscRB) where k is defined relative to the point A such that k=0 corresponds to the subcarrier centered around the point A. The function floor(A) hereinafter is floor operation to output a maximum integer not larger than the A.

[0083] Point A refers to as a common reference point. Point A coincides with subcarrier 0 (i.e., k=0) of a CRB 0 for all subcarrier spacing. Point A can be obtained from a RRC parameter offsetToPointA or a RRC parameter absoluteFrequencyPointA. The RRC parameter offsetToPointA is used for a PCell downlink and represents the frequency offset between point A and the lowest subcarrier of the lowest resource block, which has the subcarrier spacing provided by a higher-layer parameter subCarrierSpacingCommon and overlaps with the SS / PBCH block used by the UE for initial cell selection, expressed in units of resource blocks assuming 15 kHz subcarrier spacing for frequency range (FR) 1 and 60 kHz subcarrier spacing for frequency range (FR2). FR1 corresponds to a frequency range between 410MHz and 7125MHz. FR2 corresponds to a frequency range between 24250MHz and 52600MHz. The RRC parameter absoluteFrequencyPointA is used for all cased other than the PCell case and represents the frequency-location of point A expressed as in ARFCN. The frequency l ocation of point A can be the lowest subcarrier of the carrier bandwidth ( or the actual carrier). Additionally, point A may be located outside the carrier bandwidth ( or the actual carrier).

[0084] As above mentioned, the information element (IE) SCS-SpecificCarrier provides parameters determining the location and width of the carrier bandwidth or the actual carrier. That is, a carrier (or a carrier bandwidth, or an actual carrier) is determined (identified, or defined) at least by a RRC parameter offsetToCarrier, a RRCparameter subcarrierSpacing, and a RRC parameter carrierBandwidth in the SCS- SpecificCarrier IE.

[0085] The subcarrierSpacing indicates (or defines) a subcarrier spacing of the carrier. The offsetToCarrier indicates an offset in frequency domain between point A and a lowest usable subcarrier on this carrier in number of resource blocks (e.g. CRBs) using the subcarrier spacing defined for the carrier. The carrierBandwidth indicates width of this carrier in number of resource blocks (e.g., CRBs or PRBs) using the subcarrier spacing defined for the carrier. A carrier includes at most 275 resource blocks.

[0086] Physical resource blocks for subcarrier spacing configuration μ are defined within a bandwidth part and numbered form 0 to NBWP,isize,μwhere i is the number of the bandwidth part. The relation between the physical resource block nPRBμin bandwidth part (BWP) i and the common resource block nCRBμis given by Formula (2)nCRBμ= nPRBμ+ NBWP,istart,μwhere NBWP,istart,μis the common resource block where bandwidth part z starts relative to common resource block 0 (CRB0). When there is no risk for confusion the index μ may be dropped.

[0087] A BWP is a subset of contiguous common resource block for a given subcarrier spacing configuration μ on a given carrier. To be specific, a BWP can be identified (or defined) at least by a subcarrier spacing μ indicated by the RRC parameter subcarrierSpacing, a cyclic prefix determined by the RRC parameter cyclicPrefix, a frequency domain location, a bandwidth, an BWP index indicated by bwp-Id and so on. The locationAndBandwidth can be used to indicate the frequency domain location and bandwidth of a BWP. The value indicated by the locationAndBandwidth is interpreted as resource indicator value (RIV) corresponding to an offset (a starting resource block) RBstart and a length LRBin terms of contiguously resource blocks. The offset RBstartis a number of CRBs between the lowest CRB of the carrier and the lowest CRB of the BWP. The NBWP,istart,μis given as Formula (3) NBWP,istart,μ= Ocarrier+RBstart. The value of Ocarrieris provided by offsetTocarrier for the corresponding subcarrier spacing configuration μ.

[0088] AUE 102 configured to operate in BWPs of a serving cell, is configured by higher layers for the serving cell a set of at most four BWPs in the downlink for reception. At a given time, a single downlink BWP is active. The bases station 160 may not transmit, to the UE 102, PDSCH and / or PDCCH outside the active downlink BWP. A UE 102 configured to operate in BWPs of a serving cell, is configured by higherlayers for the serving cell a set of at most four BWPs for transmission. At a given time, a single uplink BWP is active. The UE 102 may not transmit to the base station 160, PUSCH or PUCCH outside the active BWP. The specific signaling (higher layers signaling) for BWP configurations are described later.

[0089] A UE 102, configured to operate in a SL BWP, is configured or preconfigured by higher layers for the serving cell or by a pre-configuration a SL BWP for sidelink reception and / or transmission. At a given time, a single SL BWP is active. The UE 102 may not transmit, to another UE 102, sidelink channel (PSCCH, PSCCH, and / or PSFCH) outside the active SL BWP.

[0090] Figure 3 is a diagram illustrating one example 300 of common resource block grid, carrier configuration and BWP configuration by a UE 102 and a base station 160.

[0091] Point A 301 is the lowest subcarrier of a CRB0 for all subcarrier spacing configurations. The CRB grid 302 and the CRB grid 312 are corresponding to two different subcarrier spacing configurations. The CRB grid 302 is for subcarrier spacing configuration =0 (i.e., the subcarrier spacing with 15kHz). The CRB grid 312 is for subcarrier spacing configuration μ =1 (i.e., the subcarrier spacing with 30kHz).

[0092] One or more carriers are determined by respective SCS-SpecificCarrier IEs, respectively. In the Figure 3, the carrier 304 uses the subcarrier spacing configuration μ=0. And the carrier 314 uses the subcarrier spacing configuration μ=1. The starting position Ngridstart,μof the carrier 304 is given based on the value of an offset 303 (i.e. Ocarrier) indicated by an offsetToCarrier in an SCS-SpecificCarrier IE. As shown in the Figure 3, for example, the offsetToCarrier indicates the value of the offset 303 as Ocarrier=3. That is, the starting position Ngridstart,μof the carrier 304 corresponds to the CRB3 of the CRB grid 302 for subcarrier spacing configuration μ=0. In the meantime, the starting position Ngridstart,μof the carrier 314 is given based on the value of an offset 313 (i.e. Ocarrier) indicated by an offsetToCarrier in another SCS-SpecificCarrier IE. For example, the offsetToCarrier indicates the value of the offset 313 as Ocarrier=1. That is, the starting position Ngridstart,μof the carrier 314 corresponds to the CRB1 of the CRB grid 312 for subcarrier spacing configuration μ=1. A carrier using different subcarrier spacing configurations can occupy different frequency ranges.

[0093] As above-mentioned, a BWP is for a given subcarrier spacing configuration μ. One or more BWPs can be configured for a same subcarrier spacing configuration μ.For example, in the Figure 3, the BWP 306 is identified at least by the μ=0, a frequency domain location, a bandwidth (LRB), and an BWP index (index A). The first PRB (i.e. PRBO) of a BWP is determined at least by the subcarrier spacing of the BWP, an offset derived by the locationAndBandwidth and an offset indicated by the offsetToCarrier corresponding to the subcarrier spacing of the BWP. An offset 305 (RBstart) is derived as 1 by the locationAndBandwidth. According to the Formulas (2) and (3), the PRBO of BWP 306 corresponds to CRB 4 of the CRB grid 302, and the PRB1 of BWP 306 corresponds to CRB 5 of the CRB grid 302, and so on.

[0094] Additionally, in the Figure 3, the BWP 308 is identified at least by the μ=0, a frequency domain location, a bandwidth (LRB), and an BWP index (index B). For example, an offset 307 (RBstart) is derived as 6 by the locationAndBandwidth. According to the Formulas (2) and (3), the PRBO of BWP 308 corresponds to CRB 9 of the CRB grid 302, and the PRB1 of BWP 308 corresponds to CRB 10 of the CRB grid 302, and so on.

[0095] Additionally, in the Figure 3, the BWP 316 is identified at least by the μ=1, a frequency domain location, a bandwidth (LRB), and an BWP index (index C). For example, an offset 315 (RBstart) is derived as 1 by the locationAndBandwidth. According to the Formulas (2) and (3), the PRBO of BWP 316 corresponds to CRB 2 of the CRB grid 312, and the PRB1 of BWP 316 corresponds to CRB 3 of the CRB grid 312, and so on.

[0096] In the present disclosure, a BWP illustrated in the Figure 3 may refer to a DL BWP, a UL BWP, or a sidelink BWP.

[0097] As shown in the Figure 3, a carrier with the defined subcarrier spacing locate in a corresponding CRB grid with the same subcarrier spacing. A BWP with the defined subcarrier spacing locate in a corresponding CRB grid with the same subcarrier spacing as well.

[0098] A base station may transmit a RRC message including one or more RRC parameters related to BWP configuration to a UE. AUE may receive the RRC message including one or more RRC parameters related to BWP configuration from a base station. For each cell, the base station may configure at least an initial DL BWP, one initial uplink bandwidth parts (initial UL BWP) and one sidelink BWP to the UE. Furthermore, the base station may configure additional UL and DL BWPs to the UE for a cell.

[0099] SIB1, which is a cell-specific system information block (SystemlnformationBlock, SIB), may contain information relevant when evaluating if a UE is allowed to access a cell and define the scheduling of other system information. SIB 1 may also contain radio resource configuration information that is common for all UEs, and barring information applied to the unified access control. The RRC parameter ServingCellConfigCommon is used to configure cell specific parameters of a UE's serving cell. The RRC parameter ServingCellConfig is used to configure (add or modify) the UE with a serving cell, which may be the SpCell or an SCell of an MCG or SCG. The RRC parameter ServingCellConfig herein are mostly UE specific but partly also cell specific.

[0100] The base station may configure the UE with a RRC parameter BWP- Downlink and a RRC parameter BWP-Uplink. The RRC parameter BWP-Downlink can be used to configure an additional DL BWP. The RRC parameter BWP-Uplink can be used to configure an additional UL BWP. The base station may transmit the BWP- Downlink and the BWP-Uplink which may be included in RRC parameter ServingCellConfig to the UE.

[0101] The UE may be configured by the based station, at least one initial BWP and up to 4 additional BWP(s). One of the initial BWP and the configured additional BWP(s) may be activated as an active BWP. The UE may monitor DCI format, and / or receive PDSCH in the active DL BWP. The UE may not monitor DCI format, and / or receive PDSCH in a DL BWP other than the active DL BWP. The UE may transmit PUSCH and / or PUCCH in the active UL BWP. The UE may not transmit PUSCH and / or PUCCH in a BWP other than the active UL BWP.

[0102] As above-mentioned, a UE may monitor DCI format in the active DL BWP. To be more specific, a UE may monitor a set of PDCCH candidates in one or more CORESETs on the active DL BWP on each activated serving cell configured with PDCCH monitoring according to corresponding search space set where monitoring implies decoding each PDCCH candidate according to the monitored DCI formats.

[0103] A set of PDCCH candidates for a UE to monitor is defined in terms of PDCCH search space sets. A search space set can be a CSS set or a USS set. A UE may monitor a set of PDCCH candidates in one or more of the search space sets.

[0104] Figure 4 is a diagram illustrating one 400 example of CORESET configuration in a BWP by a UE 102 and a base station 160.

[0105] Figure 4 illustrates that a UE 102 is configured with three CORESETs for receiving PDCCH transmission in two BWPs. In the Figure 4, 401 represent point A. 402 is an offset in frequency domain between point A 401 and a lowest usable subcarrier on the carrier 403 in number of CRBs, and the offset 402 is given by the offsetToCarrier in the SCS-SpeciflcCarrier IE. The BWP 405 with index A and the carrier 403 are for a same subcarrier spacing configuration μ. The offset 404 between the lowest CRB of the carrier and the lowest CRB of the BWP in number of RBs is given by the locationAndBandwidth included in the BWP configuration for BWP A. The BWP 407 with index B and the carrier 403 are for a same subcarrier spacing configuration μ. The offset 406 between the lowest CRB of the carrier and the lowest CRB of the BWP in number of RBs is given by the locationAndBandwidth included in the BWP configuration for BWP B.

[0106] For the BWP 405, two CORESETs are configured. As above-mentioned, a RRC parameter frequencyDomainResource in respective CORESET configuration indicates the frequency domain resource for respective CORESET. In the frequency domain, a CORESET is defined in multiples of RB groups and each RB group consists of 6 RBs. For example, in the Figure 4, the RRC parameter frequencyDomainResource provides a bit string with a fixed size (e.g., 45 bits) as like ‘11010000...000000’ for CORESET#1. That is, the first RB group, the second RB group, and the fourth RB group belong to the frequency domain resource of the CORESET#1. Additionally, the RRC parameter frequencyDomainResource provides a bit string with a fixed size (e.g., 45 bits) as like ‘00101110...000000’ for CORESET#2. That is, the third RB group, the fifth RB group, the sixth RB group and the seventh RB group belong to the frequency domain resource of the CORESET#2.

[0107] For the BWP 407, one CORESET is configured. As above-mentioned, a RRC parameter frequencyDomainResource in the CORESET configuration indicates the frequency domain resource for the CORESET #3. In the frequency domain, a CORESET is defined in multiples of RB groups and each RB group consists of 6 RBs. For example, in the Figure 4, the RRC parameter frequencyDomainResource provides a bit string with a fixed size (e.g., 45 bits) as like ‘ 11010000.. .000000’ for CORESET#3. That is, the first RB group, the second RB group, and the fourth RB group belong to the frequency domain resource of the CORESET#3. Although the bit string configured for CORESET#3 is same as that for CORESET#1, the first RB group of the BWP B isdifferent from that of the BWP A in the carrier. Therefore, the frequency domain resource of the CORESET#3 in the carrier is different from that of the CORESET#1 as well.

[0108] For the communication system, spectrum is divided into licensed spectrum and unlicensed spectrum. The NR technologies have been developed in the licensed spectrum and in the unlicensed spectrum. The operation in unlicensed spectrum, used as a complementary solution, can increase the throughput of the overall wireless communication system. However, operation in unlicensed spectrum is subject to regulatory limitations and restrictions. For example, the European Telecommunications Standards Institute (ETSI) has defined regulations for operation over the unlicensed spectrum. For example, the occupied channel bandwidth (OCB), which is defined as a bandwidth containing 99% of the signal power, should be larger than a percentage of the nominal channel bandwidth (NCB). For example, according to the ETSI regulations, the OCB should be between 70% and 100% of the NCB for 5GHz band.

[0109] An unlicensed band (or a carrier, or a subband) would be divided into one or multiple non-overlapping channels of 20MHz bandwidth in the frequency domain. For a (nominal) channel bandwidth of 20MHz, one transmission should occupy a channel bandwidth larger than what the regulation on OCB requires, for example, one transmission should be larger than 80% of the channel bandwidth of 20MHz to meet the OCB requirement. To meet the OCB requirement, the design of interlaced transmission had been introduced where each interlace transmission within a channel bandwidth can occupy a channel bandwidth being larger than what the OCB requires.

[0110] The unlicensed band (unlicensed spectrum) may be or may be not configured with operation with shared spectrum channel access. Likewise, the licensed band (licensed spectrum) may be or may be not configured with operation with shared spectrum channel access. In the present disclosure, the unlicensed band (the unlicensed spectrum) configured with operation with shared spectrum channel access can be termed the unlicensed band A (the unlicensed spectrum A). The unlicensed band (unlicensed spectrum) not configured with operation with shared spectrum channel access can be termed the unlicensed band B (the unlicensed spectrum B). The licensed band (the licensed spectrum) configured with operation with shared spectrum channel access can be termed the licensed band C (the licensed spectrum C). The licensed band(licensed spectrum) not configured with operation with shared spectrum channel access can be termed the licensed band D (the licensed spectrum D).

[0111] Interlaced transmission (i.e., interlace RB-based transmission) had been introduced to ensure the compliance with the regulations on OCB and NCB requirements. Specifically, the interlaced transmission is designed such that each interlace can occupy the channel bandwidth where the occupied channel bandwidth can fulfill the requirement of the OCB.

[0112] An interlace includes a set of resource blocks that are spread out across the bandwidth of a carrier in the frequency domain. A number of interlaces M is subject to the value of a SCS. That is, the number of interlaces M may be predefined according to a specific SCS. For example, if the SCS is equal to 15kHz, the number of resource block interlaces M is correspondingly equal to 10. If the SCS is equal to 30kHz, the number of resource block interlaces M is correspondingly equal to 5.

[0113] Figure 5 is adiagram illustrating one example 500 of interlaced transmission and reception in a BWP.

[0114] In the Figure 5, each block in the frequency domain refers to a common resource block. In the Figure 5, the subcarrier spacing is configured as 30kHz and the number of resource block interlaces M are 5. Then the interlaces are indexed from 0 to M-1. That is, an interlace m, where m = 0, 1, ..., M-1, consists of a plurality of common resource blocks with indexes {m, M+m, 2M+m, 3M+m, ... } . For example, in the Figure 5, the interlace m=0 consists of common resource blocks with indexes {0, 5, 10, 15, ...}, the interlace m=l consists of common resource blocks with indexes {1, 6, 11, 16, ...}, and so on.

[0115] In the frequency domain, a BWP 501 is determined as illustrated in Figure 3. An interlaced resource block in the BWP is denoted as where the isindexed from 0, 1, ..., in the BWP. The relation between the interlace resource blockand interlace m and the common resource block is given by. Theis the common resourceblock where the BWP starts relative to common resource block 0 (i.e., a common resource block with index 0). In the Figure 5, the BWP 501 starts in a CRB with index 4 relative to the CRB with index 0.

[0116] At least for NR-U operation in, for example, 5 GHz spectrum, a BWP may have a bandwidth of multiple of 20MHz. A sub-band may comprise 20MHz or a multiple of 20MHz bandwidth. A sub-band may also be referred to as a sub-channel, or a channel access bandwidth (e.g., a channel of 20MHz). Then a BWP may include one or more sub-bands in the frequency domain. A sub-band consists of multiple nonoverlapping RBs. The number of resource blocks within a sub-band may depend on the SCS of the BWP. For example, the sub-band size for SCS=15kHz may be equal to 108 for a 40MHz BWP, and the sub-band size for SCS=30kHz may be equal to 53 for a 40MHz BWP. That is, a sub-band is an RB set of non-overlapping and contiguous (common) resource blocks. And a sub-band can be defined by a starting common RB and an ending common RB in the frequency domain. Hereinafter, an RB set is used to refer to a sub-band. In other words, an RB set consists of non-overlapping resource blocks and can be defined by a starting common RB and an ending common RB.

[0117] As in the Figure 5, the BWP 501 includes two RB sets, i.e., a RB set 502 and a RB set 503. The RB sets within a BWP can be indexed from 0 in an increase order along with the frequency. According to higher layer (RRC) configurations, there may be a gap 504 between two consecutive RB sets. The gap in unit of resource block can be indicated by the higher layer configurations. Additionally or alternatively, there may be no gap between two RB sets. In other words, there may be a separation of zero, one, or more RBs between two contiguous RB sets within the BWP in the frequency domain.

[0118] In the Figure 5, in the frequency domain, a interlace whose RBs have a lowest CRB index within the first RB set is the interlace m = 4, while the interlace whose RBs have a lowest CRB index within the second RB set is the m = 0.

[0119] In order to ensure a fair co-existence with another NR-U node and / or another radio access technology (RAT) node such as wireless LAN node, the base station 160 and / or the UE 102 may have to perform Listen Before Talk (LBT) procedure before their transmissions. LBT procedure is also referred to as Channel Access procedure. The base station 160 and / or the UE 102 may perform the channel access procedure to determine if there is the presence of other transmission in a channel before their transmission. There may be several types of Channel Access (CA) procedures. For example, Cat-1 LBT is a channel access procedure without channel sensing. Cat-2 LBT is a channel access procedure with one shot channel sensing. Cat-2 LBT may also be referred to as Type-2 channel access procedure. Cat-1 and Cat-2 LBTs may be allowedonly inside COT. Cat-3 LBT is a channel access procedure with random backoff with a fixed contention window (CW) size. Cat-4 LBT is a channel access procedure with random backoff with an adaptive CW size. Cat-4 LBT may also be referred to as Type- 1 channel access procedure.

[0120] In a BWP, before a gNB and / or a UE attempt to transmit a signal, the gNB and / or the UE may first perform channel sensing in each RB set to check whether a channel (or one or more RB sets within the BWP allocated for transmission) is available or not for transmission. If the channel or the allocated RB set(s) is sensed to be considered to be idle (i.e., the channel is available for transmission or the gNB and / or the UE gets a channel access successfully), the gNB and / or the UE may transmit on the channel or on the allocated RB set(s). On the other hand, if the channel or the allocated RB set(s) is sensed to be considered to be busy (i.e., the channel is not available or the gNB and / or the UE does not get a channel access successfully), the gNB and / or the UE may not transmit on the channel or on the allocated RB set(s).

[0121] Vehicle-to-everything (V2X) communication technologies have been developed by 3 GPP for the automotive industry. V2X refers to a communication technology through which a vehicle exchanges information with another vehicle, a pedestrian, an object having an infrastructure, and so on. The V2X is divided into 4 types, such as vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), vehicle-to- network (V2N), and vehicle-to-pedestrian (V2P). Therefore, the V2X communication is different from the communication between the UEs and gNBs. The V2X communication enables the communication between the UEs, which is also called as sidelink. That is, sidelink communication supports UE-to-UE direct communication via a PC5 interface. In other words, sidelink communication is directly performed or communicated between one transmitting UE and one or more receiving UEs.

[0122] Sidelink communication consists of unicast, groupcast and broadcast. The unicast may refer to a communication between two UEs, i.e., one transmitting UE and one receiving UE. The groupcast and / or the broadcast may refer to a communication between one transmitting UE and multiple receiving UEs.

[0123] Currently NR Sidelink communication supports two sidelink resource allocation modes, mode 1 and mode 2. The difference between the sidelink resource allocation mode 1 and the sidelink resource allocation mode 2 lies in which determine the resource to be used for the sidelink communication.

[0124] In mode 1, the sidelink resource allocation is provided or determined by the base station and / or the network. That is, for mode 1, the base station may manage the resource allocation for the UEs. For example, a base station may allocate the resources for sidelink communication to an in-coverage UE. In sidelink resource allocation mode 1, dynamic grant, configured grant type 1 and configured grant type 2 are supported for PSSCH and PSCCH transmission. In sidelink resource allocation mode 1, for sidelink dynamic grant, the PSSCH transmission is scheduled by a DCI format 3_0. For sidelink configured grant type 1, the configured grant is provided (activated) or released (deactivated) by RRC signaling. For sidelink configured grant type 2, the configured grant is provided or released by PDCCH with the DCI format 3_0.

[0125] In mode 2, the sidelink resource allocation is determined by a TX UE itself. The UE may decide the sidelink transmission resources in a resource pool. The UE may carry out the resource allocation without involvement of the base station. These UEs may autonomously determine to select resources for sidelink communication based on a sensing-based procedure.

[0126] In mode 1, the DCI format 3_0 is used by the base station for scheduling of NR PSCCH and NR PSSCH in one cell. The base station may determine the scheduling information of NR PSCCH and NR PSSCH and provide the scheduling information to an in-coverage UE. The scheduling information may at least include a Resource pool index field, a time gap field, a HARQ process number field, a new data indicator field, a Lowest index of the subchannel allocation to the initial transmission field, SCI format 1-A fields, and so on. The Resource pool index field is used to indicate an index of a resource pool for which the sidelink transmission is scheduled and the SCI format 1-A fields here refer to the frequency resource assignment field and the time resource assignment field. That is, in mode 1, the base station may determine the time and frequency resource assignment for scheduling of sidelink transmission and then generate the corresponding fields of the scheduling information in the DCI format 3_0. A TX UE (an in-coverage UE) that received the DCI format 3_0 may transmit the PSCCH with SCI format 1-A and the PSSCH in the resource assigned by the base station based on the scheduling information in the DCI format 3_0. Moreover, the SCI format 1-A transmitted by the TX UE includes the frequency resource assignment field and the time resource assignment field which are as same as those included in the DCI format 3_0. ARX UE (an out-coverage UE and / or an in-coverage UE) that received thePSCCH with the SCI format 1-A can receive the PSSCH in the resource assigned by the base station.

[0127] In mode 2, a TX UE may autonomously determine to select resources for sidelink communication and generate the fields in SCI format 1-A to notify an RX UE of the time and frequency resource assignment. The RX UE that received the PSCCH with the SCI format 1 -A can receive the PSSCH in the resource assigned by the TX UE.

[0128] Sidelink communication supports physical channels such as Physical Sidelink Control Channel (PSCCH), Physical Sidelink Shared Channel (PSSCH), Physical Sidelink Feedback Channel (PSFCH), and Physical Sidelink Broadcast Channel (PSBCH).

[0129] The PSCCH is used for transmitting / receiving sidelink control information (e.g., the 1st-stage SCI). For example, the PSCCH indicates resource and other transmission parameters used by a UE for PSSCH reception. PSCCH transmission is associated with a DM-RS. For PSCCH, QPSK is supported.

[0130] The PSSCH is used for transmitting / receiving sidelink control information (e.g., the 2nd-stage SCI), transport block(s) of data, and channel state information (CSI). The sidelink control information herein may include information, for example, for HARQ for HARQ procedures and CSI feedback triggers, etc. At least 6 OFDM symbols within a slot are used for PSSCH transmission. PSSCH transmission is associated with a DM-RS and may be associated with a PT-RS. For PSSCH, QPSK, 16QAM, 64QAM and 256QAM are supported.

[0131] Each PSSCH transmission is associated with an PSCCH transmission. A PSCCH transmission carries the 1ststage of the SCI where the 1ststage of the SCI may schedule one or more resources for one or more PSSCH transmissions. That is, the one or more PSSCH transmissions are associated with the PSCCH transmission. In other words, the PSCCH transmission (or the 1ststage of the SCI) may be associated with one or more PSSCH transmissions.

[0132] PSFCH is used for carrying HARQ feedback over the sidelink from a UE which is an intended recipient of a PSSCH transmission to the UE which performed the PSSCH transmission. PSFCH sequence is transmitted in one PRB repeated over two OFDM symbols near the end of the sidelink resource in a slot.

[0133] The PSBCH is used for transmitting broadcast information. PSBCH occupies 9 and 7 symbols for normal and extended CP cases respectively, including the associated DM-RS.

[0134] Sidelink communication supports physical signals such as demodulation reference signal (DM-RS), phase-tracking reference signal (PT-RS), channel-state information reference signal (CSI-RS), sidelink synchronization signals.

[0135] The DMRS(s) are associated with PSCCH, PSSCH and / or PSBCH. A transmitting UE may transmit the DMRS within the associated sidelink physical channel. A receiving UE may use the DMRS to estimate and / or decode the associated sidelink physical channel.

[0136] The PT-RS is used to mitigate the effect of phase noise. A transmitting UE may transmit the PT-RS within the PSSCH transmission. The receiving UE may receive the PT-RS and use the PT-RS to mitigate the effect of phase noise.

[0137] The CSI-RS is used for measuring channel state information. A transmitting UE may transmit sidelink CSI-RS within a unicast PSSCH transmission. A receiving UE may measure the channel state information by using the CSI-RS and transmit a CSI report based on the measurement to the transmitting UE.

[0138] The Sidelink synchronization signal consists of sidelink primary and sidelink secondary synchronization signals (S-PSS, S-SSS), each occupying 2 symbols and 127 subcarriers. The sidelink synchronization signals are transmitted together with the PSBCH in a slot. Specifically, reception occasions of a PSBCH, S-PSS, and S-SSS are in consecutive symbols in a slot and form a S-SS / PSBCH block. For a SL-BWP, the S-SS / PSBCH block has a same SCS as the PSCCH, the PSSCH, and / or the PSFCH.

[0139] In various implementations of the present disclosure, a UE may be provided NR sidelink communication (pre-)configuration(s). For simplicity, (pre-)configuration(s) hereinafter refer to the NR sidelink communication (pre-)configuration(s). (Pre-)configuration(s) in the present disclosure may include configuration(s) received by system information (e.g., SIB 12) from a base station, configuration(s) received by dedicated RRC signaling (e.g., RRC configuration / parameters / message) from a base station, and / or configuration(s) preconfigured in the UE (i.e., pre-configuration). Regarding the pre-configuration, a memory unit of the UE may store the pre-configuration in advance.

[0140] In various examples or implementations of the present disclosure, (pre-)configuration(s) may include configuration(s) of one or more sidelink BWPs for sidelink communication. That is, a UE may receive the configuration(s) of the one or more BWPs included in system information, in dedicated RRC signaling, and / or in a pre-configuration. In the present disclosure, a UE may be provided by the (pre-)configuration(s) a BWP for sidelink transmissions.

[0141] In various examples or implementations of the present disclosure, a SL BWP configuration may include configuration(s) of one or more resource pools for sidelink communication. That is, the configuration(s) of the one or more resource pools (the configuration(s) related to the one or more resource pools) may be received in system information, received in dedicated RRC signaling, and / or preconfigured in a preconfiguration. According to the configuration(s), a resource pool may be indicated to be used either for sidelink communication reception or for sidelink communication transmission. Additionally or alternatively, a resource pool may be indicated to be used for both sidelink communication reception and sidelink communication transmission. Each resource pool is associated with either the sidelink resource allocation Mode 1 or the sidelink resource allocation Mode 2.

[0142] Figure 6 is a diagram illustrating one example 600 of a SL BWP and a resource pool within the SL BWP.

[0143] A UE 102 is provided by a parameter SL-BWP-Config a BWP (a SL BWP) for sidelink transmission with numerology and resource grid. The determination of a SL BWP 601 is similar as how to determine a BWP specified in the Figure 3.

[0144] In the Figure 6, each block in the time domain represents a slot. One resource pool is configured within the SL BWP 601. The resource pool can be for transmission of PSSCH, PSCCH and / or PSFCH, and / or for reception of PSSCH, PSCCH and / or PSFCH. The first RB of the resource pool relative to the first RB of SL BWP, 602, may be indicated by a parameter included in the (pre-)configurations.

[0145] Not all the slots within the SL BWP may be assigned to a resource pool within the SL BWP. That is, not all the slots may belong to a resource pool. A slot assigned to a resource pool (or a slot belongs to a resource pool) can be also referred to a slot available for the resource pool. On the contrary, a slot not assigned to a resource pool (or a slot does not belong to a resource pool) can be also referred to a slot unavailable for the resource pool. Therefore, a resource pool may consist of a plurality(set) of non-contiguous slots in the time domain. In a SL BWP, different resource pools may be assigned with different sets of slots. The UE may determine the set of slots assigned to a resource pool according to the (pre-)configurations. A transmitting UE may transmit one or more physical SL channels or one or more SL signals in one or more resource pools within a SL BWP, while a receiving UE may receive one or more physical SL channels or one or more SL signals in one or more resource pools within a SL BWP.

[0146] In the Figure 6, slot#0 refers to a first slot of a radio frame corresponding to SFN 0 of the serving cell or DFN 0. As illustrated in the Figure 6, a set of slots with indexes #4, #5, #7 and #10 belong to the resource pool. The slots in the set for a resource pool are re-indexed such that the logical slot indexes are successive from 0 to T’max-1 where the T'maxis the number of the slot in the set. For example, in the Figure 6, the four slots in the set can be re-indexed as slots with logical slot indexes 0, 1, 2, and 3. The slots available for a resource pool may be provided or indicated by a parameter sl- TimeResource and may occur with a periodicity of 10240 ms.

[0147] The OFDM symbols within a slot assigned for sidelink transmission are provided by parameters included in the (pre-)configuration. To be specific, SL transmissions can start from a first symbol indicated by a parameter sl-StartSymbol and be within a number of consecutive symbols indicated by a parameter sl-LengthSymbols . As in the Figure 6, the duration 604 starts at the third OFDM symbol 603, which is indicated by the parameter sl-StartSymbol, and consists of 11 consecutive OFDM symbols which is indicated by the parameter sl-LengthSymbols . For a slot indicated for transmission of S-SS / PSBCH blocks, the first symbol and the number of consecutive symbols is predetermined.

[0148] Sidelink control information is split into two stages, i.e., 1st-stage SCI and 2nd-stage SCI. Specifically, SCI carries onPSCCHis the 1st-stage SCI, which transports sidelink scheduling information. That is, the 1st- stage SCI is sent on PSCCH. The SCI carries on PSSCH is the 2nd-stage SCI, which transports sidelink scheduling information, and / or inter-UE coordination related information. That is, the 2nd- stage SCI is send on PSSCH.

[0149] The fields of the 1st-stage SCI formats (e.g., the SCI format 1-A) are mapped to the information bits of the 1st- stage SCI. The SCI format 1-A is used for the scheduling of PSSCH and 2nd- stage SCI on PSSCH.

[0150] The SCI format 1-A may include the following fields, e.g., Priority, Frequency resource assignment, Time resource assignment, Resource reservation period, DMRS pattern, 2nd-stage SCI format, Beta_offset indicator, Number of DMRS port, Modulation and coding scheme, Additional MCS table indicator, PSFCH overhead indication, Reserved, Conflict information receiver flag. As above-mentioned, in Mode 1, the UE may obtain the time resource assignment field and the frequency resource assignment field from DCI format 3_0 and include them in SCI format 1-A. In mode 2, the UE may determine the resource allocation for sidelink transmission and generate the time resource assignment field and the frequency resource assignment field in SCI format 1-A.

[0151] The fields defined in each of the 2nd- stage SCI formats (e.g., the SCI format 2-A, SCI format 2-B, SCI format 2-C) are mapped to the information bits of the 2nd- stage SCI. The SCI format 2-A is used for the decoding of PSSCH, with HARQ operation when HARQ- ACK information includes ACK or NACK, when HARQ -ACK information includes only NACK, or when there is no feedback of HARQ-ACK information. The SCI format 2-B is used for the decoding of PSSCH, with HARQ operation when HARQ-ACK information includes only NACK, or when there is no feedback of HARQ-ACK information.. The SCI format 2-C is used for the decoding of PSSCH and providing inter-UE coordination information or requesting inter-UE coordination information.

[0152] In NR Releases 16 / 17, sidelink communication was developed to operate in licensed spectrum. In NR Release 18, to further support commercial use cases with increased sidelink data rate, sidelink communication over unlicensed spectrum is under discussion. As above-mentioned, operation over unlicensed spectrum should fulfill different regulatory limitations and restrictions, e.g., OCB / NCB requirements. Interlaced RB-based transmission should be introduced for sidelink communication over unlicensed spectrum such that the regulatory requirement can be fulfilled. Hereinafter, unlicensed spectrum refers to the above-mentioned unlicensed spectrum A, i.e., the shared spectrum.

[0153] For the sidelink transmissions over unlicensed spectrum, whether the OCB requirement is needed to be complied with is depending on region regulation. Therefore, for an unlicensed spectrum where OCB requirement is not required or the OCB requirement can be exempted, the existing transmission scheme (in other words,contiguous RB-based transmission scheme) for sidelink physical channel and signals, which is specified in 3 GPP NR Releases 16 and 17, can be reused for sidelink communication over the unlicensed spectrum. On the other hand, for an unlicensed spectrum where OCB requirement is required, the interlaced transmission (interlace RB-based transmission) scheme can be applied to sidelink communication over the unlicensed spectrum.

[0154] In some embodiments of the present disclosure, for operation with shared spectrum channel access, to achieve a flexible and efficient design, a parameter A (i.e., a higher layer parameter A) is introduced to indicate which scheme of the contiguous RB-based transmission scheme and the interlace RB-based transmission scheme is applied for a SL BWP. Specifically, the parameter A indicates a SL BWP is (pre-)configured with contiguous RB-based PSCCH / PSSCH transmission or interlace RB-based PSCCH / PSSCH transmission. Hereinafter, the PSCCH / PSSCH transmission may refer to the PSCCH transmission, the PSSCH transmission, or both PSCCH and PSSCH transmission.

[0155] For operation with shared spectrum channel access, the UE 102 and / or the bases station 160 may determine, based on the parameter A, whether interlace RB-based transmission or contiguous RB-based transmission is used for PSCCH / PSSCH transmission in the SL BWP. On the other hand, for operation without shared spectrum channel access, the parameter A is not present in the SL BWP configuration. The UE 102 and / or the base station 160 may determine that contiguous RB-based transmission is used for SL transmission (e.g., PSSCH / PSCCH transmission) in the resource pool.

[0156] To be specific, in a case that a SL BWP configuration includes the parameter A and the parameter A is set to “a first value”, the UE 102 may determine that the SL BWP is (pre-)configured with interlace RB-based transmission, that is, the UE 102 may determine that interlace RB-based transmission is used for the PSCCH / PSSCH transmission in the SL BWP provided by the SL BWP configuration, and / or, may determine that OCB requirement is required for the SL BWP provided by the SL BWP configuration.

[0157] In a case that a SL BWP configuration include the parameter A and the parameter A is set to “a second value”, the UE 102 may determine that the SL BWP is (pre-)configured with contiguous RB-based transmission, that is, the UE 102 may determine that contiguous RB-based transmission is used for the PSCCH / PSSCHtransmission in the SL BWP provided by the SL BWP configuration, and / or, may determine that OCB requirement is not required or can be exempted for the SL BWP provided by the SL BWP configuration.

[0158] In some embodiments, the parameter A may be a common parameter to a plurality of SL resource pools which are configured within a SL BWP. That is, a SL BWP configuration may include the parameter A such that the parameter A is a common indication of which scheme is applied to all the resource pools which are configured in the SL BWP provided by the SL BWP configuration.

[0159] For convenience of illustration, hereinafter, the first case can be referred to as the case that the SL BWP is (pre-)configured with contiguous RB-based PSCCH / PSSCH transmission, while the second case can be referred to as the case that the SLBWP is (pre-) configured with interlace RB-based PSCCH / PSSCH transmission.

[0160] In the present disclosure, for operation with shared spectrum channel access, a UE may be configured with configuration information of intra-cell guard band for a SL carrier with a SCS u. Based on the configuration, the UE is provided with a number of intra-cell guard bands on the SL carrier with the SCS u. The number of intra-cell guard can be denoted as NRB-set-1. Each intra-cell guard band is defined by a start common resource block and a size in number of common resource blocks. For each intra-cell guard band, the start common resource block and the size in number of common resource blocks are provided by parameters, for example, parameters startCRB and nrofCRBs, respectively. The size of a guard band can be configured as 0 RB or non-zero RBs. For a carrier, if information of the intra-cell guard bands is not configured by parameters, the intra-cell guard bands may be predefined or predetermined for the carrier with a SCS u.

[0161] The NRB-set- 1 intra-cell guard bands separate NRB-setRB sets in the carrier with the SCS u. That is, NRB-setis the number of RB sets contained in the SL carrier. The UE may determine, based on the configuration information of the intra-cell guard bands, the frequency location (i.e., a start common resource block index and an end common resource block index) of each RB set. In other words, each RB set is defined by a start common resource block and an end common resource block in the frequency domain. An RB set consists of a plurality of contiguous common resource blocks in the frequency domain. In the present disclosure, the NRB-setRB sets are indexed from 0 to (NRB-set-1) in an ascending order of frequency location, i.e., from lowest frequencylocation to highest frequency location. That is, if an RB set A has an RB set index lower than RB set B, it implies the RB set A starts with a CRB that has a lower CRB index compared to the starting CRB of the RB set B in the frequency domain. Likewise, it implies the RB set A occupies a bandwidth that has a lower frequency compared to the bandwidth occupied by the RB set B.

[0162] For a carrier with different SCSs, an RB set may include different numbers of common resource blocks. For example, in a case that subcarrier spacing equals to 15KHz, the number of resource blocks within an RB set may be configured to be between 100 and 110. In a case that subcarrier spacing equals to 30kHz, the number of resource blocks within an RB set may be configured to be between 50 and 55 except for at most one RB set which may contain 56 RBs.

[0163] Figure 7 is a diagram illustrating one example 700 of a SL carrier with intracell guard band(s).

[0164] As in the Figure 7, a CRB grid is used to represent the common resource blocks in a carrier with a SCS μ. That is, a CRB index is used to represent a CRB in the carrier. The CRBs in the carrier are indexed from 0 in an ascending order of frequency location and starting from point A. Here, as an example in the Figure 7, the carrier 701 uses the subcarrier spacing configuration μ=1, i.e., the SCS = 30kHz.

[0165] The UE may determine, based on parameters, the starting position and carrier bandwidth of the carrier in the frequency domain. Specifically, the starting position of the carrier 701 is given based on the value of an offset 702 (i.e. Ocarrier) indicated by the above-mentioned parameter offsetToCarrier. The carrier bandwidth Ngridsize,μfor subcarrier spacing configuration of the carrier 701 is given by the above-mentioned parameter carrier Bandwidth. As depicted in the Figure 7, the carrier 701 starts from the CRB with index 2, i.e., the Ngridstart,μ= 2, and includes a plurality of contiguous CRBs with index from 2 to 107. That is, the carrier bandwidth Ngridsize,μof the carrier 701 in number of RBs is 106.

[0166] The starting position Ngridstart,μof the carrier is also the starting position of an RB set with a lowest index among the NRB-setRB sets. The ending position of the carrier is also the ending position of an RB set with a highest index among the NRB-setRB sets.

[0167] The UE may determine, based on the configuration information of intra-cell guard band for the SL carrier, frequency locations (i.e., starting CRBs and ending CRBs) for the NRB-setRB sets.

[0168] As illustrated in the Figure 7, the number of intra-cell guard band is equal to 1, i.e., NRB-set-1=1. As above-mentioned, the intra-cell guard band 703 can be defined by a start CRB and a size in number of CRBs provided by a parameter startCRB and a parameter nrofCRBs, respectively. Specifically, the parameter startCRB indicates an RB offset relative to the starting CRB of the carrier 701. A CRB index of a starting CRB of an intra-cell guard band is given by its corresponding parameter startCRB and the Ngridstart,μof the carrier 701. In the Figure 7, for instance, the parameter startCRB indicates an RB offset as 50. The starting CRB of the intra-cell guard band 703 is determined by the summation of the RB offset and the Ngridstart,μ, i.e., the starting CRB of the intra-cell guard band 703 is the CRB with index 52. And the intra-cell guard band 703 includes 6 CRBs that is provided by the parameter nrofCRBs.

[0169] Then the intra-cell guard band 703 separates two RB sets 704 and 705 in the carrier 701, i.e., NRB-set=2. Within the carrier, the RB sets are indexed in increasing order from 0 to NRB-set-1 from lowest frequency location to highest frequency location.

[0170] The RB set 704 is indexed with 0, i.e., the RB set 704 refers to the RB set 0 within the carrier 701. Likewise, the RB set 705 can be indexed with 1, i.e., the RB set 705 refers to the RB set 1 within the carrier 701.

[0171] The starting position (the starting CRB) of the RB set 704 is the starting position Ngridstart,μof the carrier 701. The ending CRB of the RB set 704 is determined based on the starting position Ngridstart,μof the carrier 701 and the starting CRB of the guard band 703. Additionally, the starting CRB of the RB set 705 is determined based on the starting position Ngridstart,μof the carrier 701, the starting CRB of the guard band 703, and the size of the the guard band 703 by the parameter nrofCRBs. The ending CRB of the RB set 705 is determined based on the starting position Ngridstart,μof the carrier 701 and the size Ngridsize,μof the carrier 701.

[0172] Each CRB on the carrier is mapped to an interlace m where the mapping between CRBs and interlaces are performed cyclically from 0 to M-1 in an order of increasing frequencies of CRBs. As in the Figure 7, CRBs on the carrier are mapped to an interlace cyclically from 0 to 4 in the order of increasing frequencies of the CRBs and starting from the lowest frequency of a CRB.

[0173] For operation with shared spectrum channel access, in the frequency domain, a SL BWP in a carrier can be (pre-)configured to include one, more or all of RB sets that contained in the carrier. As depicted in the Figure 7, a SL BWP 706 is configuredto include all RB sets that are contained in the carrier 701. That is, the number of RB sets within the SL BWP 706 is same as that within the carrier 701. Likewise, the RB sets within a SL BWP can be numbered in increasing order from 0 to NRB-setBWP-1 where the NRB-setBWPis the number of RB sets contained in the SL BWP. In the Figure 7, the value of NRB-setBWPis equal to that of NRB-set. The NRB-setBWPRB sets are indexed in increasing order from 0 to NRB-setBWP-1 from lowest frequency location to highest frequency location.

[0174] Likewise, the UE may be configured with one or more SL resource pools within the SL BWP. A SL resource pool can be (pre-)configured to include integer number of RB sets wherein the lowest RB of the SL resource pool is aligned with the lowest RB of lowest RB set contained in the SL resource pool and the highest RB of the SL resource pool is aligned with the highest RB of highest RB set contained in the SL resource pool. For a resource pool, the RB sets included in the SL resource pool can be denoted as NRB-setRPwhere NRB-setRPis less than or equal to NRB-setBWP. The NRB-setRPRB sets included in the resource pool are indexed in increasing order from 0 to NRB-setRP-1 from lowest frequency location to highest frequency location.

[0175] If a SL BWP includes more than one RB set in the frequency domain, the SL BWP may also include guard band(s) between any two adjacent RB sets among the RB sets included in the SL BWP. Similarly, if a SL resource pool includes more than one RB set in the frequency domain, the SL resource pool may also include guard band(s) between any two adjacent RB sets among the RB sets included in the SL resource pool.

[0176] As illustrated in Figure 7, two SL resource pools, i.e., a SL resource pool 707 and a SL resource pool 708 are configured in the SL BWP 706. The SL resource pool 707 is configured to include the RB set 704, the RB set 705, and the guard band 703 in the frequency domain. The SL resource pool 708 is configured to include the RB set 705 in the frequency domain. That is, different SL resource pools can be configured with different number of RB sets within a SL BWP, which are depending on configured bandwidths of the resource pools. The resource pool 707 includes NRB-setRP =2 RB sets and the resource pool 708 includes NRB-setRP=1 RB set.

[0177] As above-mentioned, a PRB grid is used to represent the physical resource blocks in a SL BWP. That is, a PRB index is used to represent a PRB in the SL BWP. The PRBs in the BWP are indexed from 0 in an order of increasing frequencies. A PRBin a SL BWP corresponds to a CRB in a carrier. Likewise, a PRB in a BWP corresponds to an RB of an interlace m in a carrier. As illustrated in the Figure 7, the PRB with index 0 corresponds to the CRB with index 2, the PRB with index 1 corresponds to the CRB with index 3, and so on. Likewise, the PRB with index 0 corresponds to an RB of interlace m=2. The PRB with index 1 corresponds to an RB of interlace m=3.

[0178] In the Figure 7, the resource pool 707 starts in a RPB with index 0 relative to the starting PRB of the SL BWP (i.e., PRB with index 0), while the resource pool 708 starts in a RPB with index 56 relative to the starting PRB of the SL BWP (i.e., PRB with index 0). A SL BWP and / or a resource pool is configured not to include parts of an RB set. In the present disclosure, a SL BWP and / or a resource pool may be configured to start on an RB with a lowest CRB index within a first RB set and to end an RB with a largest CRB index within a second RB set. The first RB set and the second RB set can refer to a same RB set or different RB sets within the carrier. In other words, a starting RB of a SL BWP and / or a SL resource pool is a starting RB of an RB set. Likewise, an ending (last) RB of a SL BWP and / or a SL resource pool is an ending RB of an RB set.

[0179] In a resource pool, a sub-channel is a minimum resource allocation granularity in frequency domain for PSCCH / PSSCH transmission. In the present disclosure, different sub-channel structures are designed depending on whether contiguous RB-based PSCCH / PSSCH transmission or interlace RB-based PSCCH / PSSCH transmission is (pre-)configured for the SL BWP. In the above- mentioned first case, the UE 102 may determine that a sub-channel consists of multiple contiguous PRBs in the frequency domain, while in the above-mentioned second case, the UE 102 may determine that a sub-channel in an RB set includes PRBs of one or more interlaces contained within the RB set.

[0180] The determination of sub-channels for the first case is similar as the existing design of sub-channel specified in NR Releases 16 and 17 where a sub-channel consists of contiguous PRBs in the frequency domain. In the second case, a sub-channel may be associated with one or more interlaces in an RB set. That is, a sub-channel may include PRBs of one or more interlaces contained in an RB set in the frequency domain where the PRBs of one or more interlaces are not contiguous in the frequency domain. An RB set of a resource pool consists of one or more sub-channels in the frequency domain. A resource pool consists of one or more sub-channels in the frequency domain.

[0181] Figure 8 is a diagram illustrating one example 800 of sub-channel determination in a resource pool. In the example 800, the above-mentioned parameter A, which is included in the SL BWP configuration, is set to “a second value”. That is, the contiguous RB-based PSCCH / PSSCH transmission is applied in the resource pool. A PSSCH transmission / reception may be performed in one or more contiguously allocated sub-channels in the frequency domain where each sub-channel consists of multiple contiguous RBs in the frequency domain.

[0182] In the frequency domain, the UE may determine frequency location for a resource pool according to parameters included in the SL resource pool configuration. For example, a parameter sl-RB-Number indicates the number of PRBs, APRB, in the resource pool and a parameter sl-StartRB-Subchannel indicates the lowest RB index of the sub-channel with the lowest index in the resource pool with respect to the lowest RB index of the SL BWP. The lowest RB of the sub-channel with the lowest index in the resource pool is also the lowest RB of the resource pool. For operation with shared spectrum channel access, the parameters sl-RB-Number and sl-StartRB-Subchannel should provide appreciate values such that the lowest RB of the resource pool is aligned with the lowest RB of lowest RB set in the resource pool and the highest RB of the resource pool is aligned with the highest RB of highest RB set in the resource pool.

[0183] In addition, the SL resource pool configuration also includes parameters to indicate, e.g., the number of sub-channels contained in the resource pool and a number of contiguous resource blocks contained in a sub-channel in the resource pool. The parameter sl-NumSubchannel included in the configuration of the resource pool is used to indicate the number of sub-channels, NsubchannelSL, that are contained in the resource pool. That is, the resource pool consists of NsubchannelSLsub-channels. The parameter sl- SubchannelSize included in the configuration of the resource pool is used to indicate the number of contiguous RBs, Ksub, that are contained in a sub-channel. That is, a subchannel consist of Ksubcontiguous PRBs in the frequency domain.

[0184] As depicted in the Figure 8, the resource pool 801 is (pre-)configured to include two RB sets and one guard band between these two RB sets, i.e., the RB set 802, the guard band 803, and the RB set 804 in the frequency domain. The SL resource pool 801 in the Figure 8 is as same as the SL resource pool 707 that is specified in the Figure 7. That is, the above description in the Figure 7 can be applied to that in the Figure 8.

[0185] For example, in the Figure 8, the parameter sl-NumSubchannel indicates that NsubchannelSLis 5. That is, the resource pool 801 consists of 5 contiguous sub-channels in the frequency domain. The NsubchannelSLsub-channels are indexed in increasing order from 0 to NsubchannelSL-1 from lowest frequency location to highest frequency location.

[0186] The first RB (i.e., the lowest RB, the start RB) of the first sub-channel (i.e., the sub-channel with the lowest subchannel index, the sub-channel #0) of the resource pool 801 in the SL BWP may be given based on the parameter sl-StartRB-Subchannel. For operation with shared spectrum channel access, the first RB of the sub-channel with index 0 in the resource pool 801 is aligned with the first RB of the RB set 802.

[0187] In the Figure 8, for example, Ksubis indicated as 20 resource blocks. The sub-channel #0 includes first Ksub=20 contiguous resource blocks, the sub-channel# 1 includes second Ksub=20 contiguous resource blocks starting from a PRB adjacent to the last PRB of the sub-channel#0, and so on. Specifically, as depicted in the Figure 8, the subchannel #0 includes Ksub=20 contiguous resource blocks with CRB indices from 2 to 21, the subchannel #1 includes Ksub=20 contiguous resource blocks with CRB indices from 22 to 41, the subchannel #2 includes Ksub=20 contiguous resource blocks with CRB indices from 42 to 61, the subchannel #3 includes Ksub=20 contiguous resource blocks with CRB indices from 62 to 81, and the subchannel #4 includes Ksub=20 contiguous resource blocks with CRB indices from 82 to 101. When the NPRBis not the integer multiple of the Ksub, the remaining PRBs 805 (i.e., the last NPRBmod KsubPRBs in the resource pool) are not used for PSCCH / PSSCH transmission.

[0188] In a case that a resource pool includes multiple RB sets and one or more guard bands, for sub-channels contained in the resource pool 801, some sub-channels may consist of RBs that are contained in one RB set, some sub-channels may consist of RBs that are contained in two RB sets and RBs that are contained in one guard band, and / or some sub-channels may consist of RBs that are contained in one RB set and RBs that are contained in one guard band.

[0189] In the above-mentioned second case, for a resource pool where interlace RB- based PSCCH / PSSCH transmission is (pre-)configured, each RB of the resource pool is mapped to an RB of an interlace m. Furthermore, each RB within a resource pool is mapped to an interlace. In other words, in the present disclosure, a resource pool mayconsist of a plurality of interlaces. In the frequency domain, a resource pool is divided into a number of interlaces M where each interlace consists of non-contiguous (common) resource blocks. As above-mentioned, the value of M is determined per SCS.

[0190] In the second case, a sub-channel is defined and indexed within 1 RB set within a resource pool. That is, the mapping between sub-channel and interlace(s) is performed in each RB set within a resource pool. In some embodiments, a parameter included in the resource pool configuration can be used to indicate the number of K interlaces per sub-channel in the resource pool to UE. That is, a sub-channel consists of K contiguous interlaces within 1 RB set. The value of K can be equal to 1 or larger than 1. For example, in case of SCS=15kHz (i.e., 34=10), the value of may be indicated as 1 or 2. In case of SCS=30kHz (i.e., M=5), the value of K may be indicated as 1.

[0191] Figure 9 is a diagram illustrating one example 900 of sub-channel determination in a resource pool by a UE 102. In the example 900, the SCS of the resource pool is 30kHz and K is indicated as 1, that is, one sub-channel includes 1 interlace within 1 RB set. In the example 900, the above-mentioned parameter A, which is included in the SL BWP configuration, is set to “a first value”. That is, the interlace RB-based PSCCH / PSSCH transmission is applied in the resource pool. A PSSCH transmission / reception may be performed in one or more contiguously allocated subchannels where each sub-channel consists of K interlace(s) in the frequency domain. Herein, the contiguously allocated sub-channels imply that the sub-channel indexes of the allocated sub-channels are contiguous.

[0192] In the frequency domain, the UE may determine, based on a parameter included in the resource pool configuration, that a resource pool includes which RB set(s) contained by the SL BWP. The parameter indicates which RB index(s) of the RB sets contained in the SL BWP to be included in a resource pool. As depicted in the Figure 9, the parameter indicates the RB indexes 0 and 1, which means that the resource pool 901 is configured to include the first RB set 902 of the SL BWP, the second RB set 904, and guard band 903 between these two adjacent RB sets 902 and 904 in the frequency domain.

[0193] The UE 102 may determine sub-channels for each RB set in the resource pool 901. In the present disclosure, for operation with shared spectrum channel access and when the parameter is set to “the first value”, the sub-channel is indexed per RB set and is periodically indexed across multiple RB sets within the resource pool. Thesub-channel with same index is mapped to K interlace(s) with the same index(s) in different RB sets. Hereinafter, NsubChannelRBsetis used to denote the number of subchannels per RB set. The NsubChannelRBsetsub-channels in an RB set are indexed in increasing order from 0 to NsubChannelRBset- 1 wherein the sub-channel #0 is mapped to interlace 0 to (K-1), the sub-channel #1 is mapped to interlaces K to (2*K-1), the subchannel #3 is mapped to interlaces 2*K to (3*K-1), and so on.

[0194] In some embodiments, the number of sub-channels per RB set, NsubChannelRBsetmay be indicated by the above-mentioned parameter sl-NumSub channel. For example, in the example 900, the parameter sl-NumSubchannel may indicate NsubChannelRBset= 5 to the UE.

[0195] In some embodiments, the number of sub-channels per RB set, NsubChannelRBse,tmay be given based on M and K. The UE may determine that NsubChannelRBsetis equal to (M / K). For example, in the example 900, the UE may determine that NsubChannelRBset= (M / K)=5.

[0196] As depicted in the Figure 9, the RB set 902 includes NsubChannelRBset=5 subchannels. The sub-channels within in the RB set 902 are indexed from 0 to 4. Within the RB set 902, the sub-channel with index 0 includes the interlace with index m = 0, the sub-channel with index 1 includes the interlace with index m = 1, sub-channel with index 2 includes the interlace with index m = 2, sub-channel with index 3 includes the interlace with index m = 3, and sub-channel with index 4 includes the interlace with index m = 4. In other words, within the RB set 902, the sub-channel with index 0 includes resource blocks in the interlace with index m = 0 contained in the RB set 902, the sub-channel with index 1 includes resource blocks in the interlace with index m = 1 contained in the RB set 902, and so on.

[0197] Similarly, the RB set 904 includes NsubChannelRBset=5 sub-channels. The subchannels within in the RB set 904 are indexed from 0 to 4. Within the RB set 904, the sub-channel with index 0 includes the interlace with index m = 0, the sub-channel with index 1 includes the interlace with index m = 1, sub-channel with index 2 includes the interlace with index m = 2, sub-channel with index 3 includes the interlace with index m = 3, and sub-channel with index 4 includes the interlace with index m = 4. In other words, within the RB set 904, the sub-channel with index 0 includes resource blocks in the interlace with index m = 0 contained in the RB set 904, the sub-channel with index 1 includes resource blocks in the interlace with index m = 1 contained in the RB set 904,and so on. As in the Figure 9, a sub-channel is defined within each RB set and does not include resource block in guard band 903.

[0198] For operation with shared spectrum channel access, whether to use interlace RB-based PSFCH transmission depends on whether OCB requirement is required in a SL BWP. In a case where OCB requirement is required, the interlace RB-based PSFCH transmission can be applied to PSFCH transmission such that the PSFCH transmission can comply with the OCB requirement. On the other hand, in a case where the OCB requirement is not required or the OCB requirement can be exempted, the PSFCH transmission can be performed in one PRB in the frequency domain.

[0199] In the present disclosure, for operation with shared spectrum channel access, for a resource pool, the UE may determine, based on whether a parameter (e.g., sl- TransmissionStructureForPSFCH) is included in the resource pool configuration, whether one PSFCH transmission is performed based on interlace transmission or one PSFCH transmission is performed on one PRB. Moreover, for a resource pool which includes multiple RB sets and one or more guard bands, one PSFCH transmission / reception is performed by the UE 102 within an RB set of a resource pool. The UE 102 does not use resource blocks in guard band(s) for the PSFCH transmission / reception.

[0200] To be specific, in a case that a resource pool configuration includes the parameter sl-TransmissionStructureForPSFCH, the UE 102 may determine interlace RB-based transmission is used for the PSFCH transmission in the resource pool. In a case that a resource pool configuration does not include the parameter sl- TransmissionStructureFor PSFCH, the UE 102 may determine that one RB is used for one PSFCH transmission.

[0201] In the present disclosure, the configuration of the parameter sl- Tr ansmissionStructureFor PSFCH in a SL resource pool configuration accords with the configuration of the above-mentioned parameter A in a SL BWP configuration. Here, the SL BWP configuration includes information to indicate resource pool configurations on the SL BWP. Specifically, in a case that the above-mentioned parameter A in the SL BWP configuration is set to “the first value” for a SL BWP, a resource pool configuration is (pre-)configured to include the parameter sl- TransmissionStructureForPSFCH. In a case that the above-mentioned parameter A isset to “the second value” for a SL BWP, a resource pool configuration is (pre-)configured not to include the parameter sl-TransmissionStructureForPSFCH.

[0202] For a sidelink transmission over the unlicensed spectrum, the UE 102 may apply LBT procedure before performing a SL transmission. When LBT procedure is applied, the UE 102 senses the channel to determine whether the channel is free or busy. Specifically, Physical layer may perform an LBT procedure before a SL transmission. In a case that the channel is sensed free, the UE 102 (i.e., the Layer 1 of the UE 102) may perform the SL transmission. On the other hand, in a case that the channel is sensed busy, the UE 102 (i.e., the Layer 1 ofthe UE 102) may not perform the SL transmission.

[0203] Hereinafter, for purposes of illustration, a TX UE refers to a UE which transmits a PSSCH in a resource pool. A RX UE refers to a UE which receives the PSSCH in a resource pool. In response to the reception of the PSSCH, the RX UE may transmit, to the TX UE, a PSFCH transmission with HARQ-ACK information in a PSFCH resource of the resource pool. The HARQ-ACK information corresponding to one HARQ-ACK information bit may include ACK or NACK, or only NACK. The TX UE may receive the PSFCH transmission from the RX UE in corresponding PSFCH resource of the resource pool. For convenience of illustration, “PSFCH occasion” hereinafter may refer to either “PSFCH transmission occasion” or “PSFCH reception occasion”. Form the RX UE perspective, “PSFCH occasion” hereinafter may refer to “PSFCH transmission occasion”, while, from the TX UE perspective, “PSFCH occasion” hereinafter may refer to “PSFCH reception occasion”.

[0204] Given that LBT failure would prevent UE from transmitting PSFCH, for a resource pool, it is beneficial to configure multiple PSFCH occasions for an associated PSCCH / PSSCH transmission in time domain such that opportunities of PSFCH transmissions or receptions for an associated PSCCH / PSSCH transmission could be increased.

[0205] In the present disclosure, the resource pool can be configured with one or multiple PSFCH occasions provided by the indication (e.g., parameter E). That is, the resource pool configuration may include the indication (e.g., the parameter E) to indicate a number of PSFCH occasions for PSFCH transmission and PSFCH reception. The number of PSFCH occasions can be denoted as In other words, theparameter E is used to indicate that one PSCCH / PSSCH transmission hasassociated candidate PSFCH occasions. The value ofcan be (pre-) configured as 1, 2, 3, or 4. In a case that the parameter E is not present in the resource pool configuration, the UE may determine that there is 1 PSFCH occasions associated with one PSCCH / PSSCH transmission, i.e.,

[0206] For a PSSCH reception in a slot, there arePSFCH occasions associated with the PSSCH recep Jrtion wherein the indicated value of thePSFCH occasions may be 1 or more than 1. For a PSSCH reception in a slot, its associated PSFCH occasions can be indexed from 1 to in ascendingorder in time. The RX UE may attempt to transmit the PSFCH over a number of first slots that include PSFCH resources.

[0207] In the time domain, the determination of the PSFCH occasionsassociated with a PSSCH reception in a slot are at least based on a minimum time gap and the slot where PSSCH is received. The minimum time gap is a number of slots between the PSSCH reception and its associated PSFCH transmission. The minimum time gap is used to accommodate the processing time of the RX UE, for example, including the PSCCH / PSSCH processing / decoding time and the generation time of HARQ feedback. The specific value of the minimum time gap is (pre-)configured by the SL resource pool configuration.

[0208] Specifically, the first PSFCH occasion in the associated PSFCHoccasions is in a first slot that includes PSFCH resources and is at least a number of slots (i.e., the minimum time gap in unit of slots) after the slot of the PSSCH reception, the second PSFCH occasion in the associated PSFCH occasions is in asequential (next) slot that includes PSFCH resources right after the first slot where the first PSFCH occasion locates, and so on.

[0209] If a RX UE receives a PSSCH in a slot in a resource pool, the RX UE may transmit PSFCH with HARQ-ACK information in a first PSFCH occasion among the associatedPSFCH occasions in the resource pool. If the RX UE fails to transmit PSFCH in the first PSFCH occasion, the RX UE may attempt to transmit PSFCH in the second PSFCH occasion, and so on. The RX UE attempts to transmit PSFCH in a PSFCH occasion if the RX UE fails to transmit PSFCH in previous PSFCH occasion(s). On the other hand, if the RX UE succeeds in transmitting PSFCH in a PSFCH occasion, the RX UE may not transmit PSFCH in PSFCH occasion(s) after thePSFCH occasion. Likewise, a TX UE may attempt to receive PSFCH in the first PSFCH occasion. If failed, the TX UE may attempt to receive PSFCH in the next PSFCH occasion. If the TX UE succeeds in receiving PSFCH in a PSFCH occasion, the TX UE may not attempt to receive PSFCH in PSFCH occasion(s) after the PSFCH occasion.

[0210] Figure 10 is a diagram illustrating one example 1000 of determining PSFCH occasions in time domain in a resource pool. For convenience of illustration, in the example 1000, the resource pool includes one RB set 1001 in the frequency domain, the value ofis configured to 2 in the resource pool, and the number of slots(i.e., the above-mentioned minimum time gap) is configured to 2.

[0211] In the time domain, PSFCH resources may be (pre-)configured periodically with a periodin the unit of slots within the resource pool wherein the value ofis indicated by a parameter (e.g., a parameter sl-PSFCH-Period ) which is included in the resource pool configuration. For example, the value of may beindicated as 0, 1, 2 or 4. In a case the value of is indicated to be 0, the UE 102may determine there is no resource for PSFCH and the PSFCH transmissions (i.e., the HARQ feedbacks for PSSCH transmissions) in the resource pool are disabled. In a case that the value of is indicated to not be 0, the UE 102 may determine thatresources for PSFCH are periodically configured every slot(s) within theresource pool.

[0212] Specifically, the UE 102 may determine, in the resource pool, whether a slot includes the PSFCH resources according to the slot index k and the value ofIn a case that k mod the SL UE 102 may determine that the slot with theslot index k includes PSFCH resources. Otherwise, the SL UE 102 may determine the slot with the slot index k does not include PSFCH resources. As depicted in the Figure 10, the value of is indicated as 4, the slots with indexes k=0, 4, 8, 12 includesthe PSFCH resources. A slot including the PSFCH resources can be also called as a PSFCH slot. In the Figure 10, the slots with indexes k=0, 4, 8, 12 are the PSFCH slots.

[0213] For a PSFCH slot, there are PSSCH slots associated with thePSFCH slot. For a PSFCH slot, its associated PSSCH slots are determinedbased on the minimum time gap. For a PSFCH slot, its associatedPSSCH slots are latestslots that are at least a number of slots (i.e., the minimum time gap) of the resource pool before the PSFCH slot. For example, in the Figure 10, for the firstPSFCH occasion 1007 in slot#8, its associated PSSCH slots are slot#3, slot #4,slot# 5, and slot#6. Herein, a PSSCH slot refers to a slot where a PSSCH transmission or reception may occur. A PSSCH slot can be also referred to as a slot in the resource pool. For a PSFCH slot, its associated PSSCH slots refers to those slots in which PSSCHs are transmitted or received and HARQ-ACK information of the PSSCHs is transmitted or received in the PSFCH slot.

[0214] In a case that there are multiple PSFCH occasions configured for a PSSCH transmission or reception in a slot, mapping between PSFCH slot and its associated PSSCH slots are in a PSFCH occasion specific way. For a n-th PSFCH occasion in a PSFCH slot, its associated^SSCH slots refer to those slots in whichthe PSSCHs may be transmitted or received and ra-th PSFCH occasion of the PSSCHs are in the PSFCH slot. For example, in the Figure 10, for the second PSFCH occasion 1008 in slot#8, its associatedPSSCH slots are slot#2, slot #1, slot# 0, and a slot prior to the slot#0 in the resource pool.

[0215] In the example 1000, for a PSSCH reception in a slot in the resource pool, one PSSCH reception may be associated with 2 PSFCH transmission occasions. The RX UE may attempt to transmit the PSFCH over a number of first =2 slotsthat include PSFCH resources and are at least the number of slots after the slot of the PSSCH reception.

[0216] When the RX UE receives the PSSCH 1005 in the slot with index 1 in the resource pool, the RX UE may determine that the first =2 slots (time locationof the PSFCH transmission occasion) are the slot with index 4 and the slot with index 8. Specifically, the first PSFCH transmission occasion associated with the PSSCH reception 1005 is in the slot with index 4, while the second PSFCH transmission occasion associated with the PSSCH reception 1005 is in the slot with index 8.

[0217] Likewise, when the RX UE receives the PSSCH 1006 in the slot with index 3 in the resource pool, the RX UE may determine that the first =2 slots (timelocation of the PSFCH transmission occasion) are the slot with index 8 and the slot with index 12. Specifically, the first PSFCH transmission occasion associated with the PSSCH reception 1006 is in the slot with index 8, while the second PSFCH transmission occasion associated with the PSSCH reception 1006 is in the slot with index 12.

[0218] In response to a PSSCH reception, the RX UE may attempt to transmit PSFCH in the first PSFCH transmission occasion associated with the PSSCH reception. If the RX UE fails to transmit PSFCH in the first PSFCH transmission occasion due to, for example, LBT failure, the RX UE may attempt to transmit PSFCH in the second PSFCH transmission occasion associated with the PSSCH reception. If the RX UE transmitted PSFCH in the first PSFCH transmission occasion, the RX UE may not attempt to transmit PSFCH in the second PSFCH transmission occasion.

[0219] In other words, the UE may determine time resource of one or multiple PSFCH occasions associated with a PSSCH reception in a slot in the resource pool at least based on one, more or all of the (i) the time location of the PSSCH reception, (ii) the number of slots (i.e., the minimum time gap configured by the SL parameter), (iii) the value of and (iv) the value of

[0220] To be more specific, the time resource of a PSFCH occasion may occupies two OFDM symbols in the time domain. As above-mentioned, a parameter sl- StartSymbol indicates a starting symbol used for sidelink in a slot. A parameter sl- LengthSymbols indicates a number of consecutive symbols used for sidelink in a slot. For example, in Figure 10, the parameter sl-StartSymbol indicates that a starting symbol used for sidelink in a slot is the third symbol 1002 in a slot. And the parameter sl- LengthSymbols indicates the number of consecutive symbols 1003 used for sidelink in a slot is 12. That is, the 1003 consists of 12 consecutive OFDM symbols in a slot. The symbol 1002 is the first symbol of the consecutive symbols 1003. As in the Figure 10, symbols within 1003 in a slot are configured for sidelink. On the other hand, symbols outside 1003 in a slot (i.e., the first two symbols of a slot) are not configured for sidelink. The UE may not transmit the PSSCH in symbols which are not configured for sidelink in a slot. The UE may transmit the PSSCH in symbols which are configured for sidelink in a slot.

[0221] In a slot where PSFCH resources are not configured, the UE may transmit the PSSCH in the consecutive symbols 1003 except the first symbol and the last symbol of 1003 where the first symbol of 1003 (i.e., the symbol 1002) is used as an automatic gain control (AGC) symbol and the last symbol of 1003 (i.e., the symbol 1005) is used as a guard symbol. An AGC symbol is used to adjust the strength of the received signal in order to reduce the quantization error or the clipping of the received signal at theanalog to digital converter. A guard symbol is used for timing adjustment and for switch between transmission and reception by a UE.

[0222] However, in a slot where PSFCH resources are configured, a portion of the consecutive symbols 1003 may be used for PSFCH. Specifically, a second-to-last symbol in the 1003 is used for PSFCH transmission and therefore can be called as PSFCH symbol. The OFDM symbol prior to the PSFCH symbol is used as an AGC symbol. The signal transmitted in the PSFCH symbol would be duplicated in the AGC symbol. In other words, the AGC symbol is a duplicated symbol of the PSFCH symbol. A symbol 1004 prior to the AGC symbol is used as a guard symbol between the PSSCH transmission and the PSFCH transmission. As shown in the Figure 10, PSSCH and PSFCH may be multiplexed in the time domain in the slot where PSFCH resources are configured.

[0223] As in the Figure 10, the second PSFCH occasion associated with the PSSCH 1005 and the first PSFCH occasion associated with the PSSCH 1006 locate in a same slot, i.e., the slot with index 8. It is necessary to separate frequency resources for different PSFCH occasions such that the frequency resource collision can be avoided.

[0224] As above-mentioned, when a resource pool is configured withPSFCH occasions, for a PSSCH reception in a slot, there are PSFCH occasionsassociated with the PSSCH in different slots in the time domain. Similarly, for a same PSFCH slot, there are partitions of frequency resources where each partitionis associated with a PSFCH occasion located in the PSFCH slot. For example, in the Figure 10, PSFCH resources indicated for PSFCH transmission and reception are partitioned into parts. For example, the partition 1007 is used for the firstPSFCH occasion in slot#8, while the partition 1008 is used for the second PSFCH occasion in slot#8. Specifically, the partition 1007 refers to the frequency resources of a first PSFCH occasion in slot#8 wherein the first PSFCH occasion is associated to the PSSCH reception in slot#3, while the partition 1008 refers to the frequency resources of a second PSFCH occasion in slot#8 wherein the second PSFCH occasion is associated to the PSSCH reception in slot#l . The partition 1009 refers to the frequency resources of a first PSFCH occasion in slot#4 wherein the first PSFCH occasion is associated to the PSSCH reception in slot#l.

[0225] A PSSCH transmission in a slot (i.e., one or multiple sub-channels in a slot) associates withPSFCH occasions in different PSFCH slots. APSFCH slot may also have PSFCH occasions wherein the PSFCHoccasions have same time resources but separate frequency resources, i.e., separate PRBs. ThePSFCH occasions in a PSFCH slot are associated with PSSCH transmission in different slots.

[0226] For a PSFCH slot, the separate sets of PRBs are (pre-)configured for thePSFCH occasion. A parameter list provides indication(s) whereineach indication in the list indicates a set of PRBs that are actually used for PSFCH transmission and reception of a PSFCH occasion of a PSCCH / PSSCH transmission in a slot. That is, the parameter list shall be (pre-)configured such that candidatePSFCH occasion(s) are associated withdifferent PRB sets. The length of this parameter list is aligned with the value of the Therefore, for a PSCCH / PSSCHreception in a slot, the UE may determine the frequency resources for each PSFCH occasion based on corresponding indication in the parameter list. That is, for a n-th PSFCH occasion wherethe UE may determine a set of PRBs based on the n-th indication provided by the parameter list.

[0227] Each indication provides a bitmap where leftmost bit of the bitmap refers to the lowest RB index in the resource pool, and so on. The size of bitmap is same as the number of PRBs included in the resource pool. Each bit in the bitmap corresponding to a PRB in the resource pool. Each bit in the bitmap has a one-to-one mapping to each PRB in the resource pool. Value 0 in the bitmap indicates that the corresponding PRB is not used for PSFCH transmission and reception while value 1 indicates that the corresponding PRB is used for PSFCH transmission and reception. Therefore, the UE may determine, based on the n-th indication, a set of PRBs for the n-th PSFCH occasion in the resource pool for P SF CH transmission with HARQ-ACK information in response to its associated PSCCH / PSSCH in a slot. Note that, in the present disclosure, for a resource pool including intra-cell guard band, the PRBs within the intra-cell guard band are not used for PSFCH transmission. That is, bits in the bitmap corresponding to PRBs within the intra-cell guard band should be set to value 0.

[0228] For example, in the Figure 10, for a PSCCH / PSSCH reception 1005 in slot #1, the UE may determine, based on the first indication, a set of PRBs 1009 in slot #4in the resource pool for the first PSFCH occasion of the PSCCH / PSSCH reception 1005, and determine, based on the second indication, a set of PRBs 1008 in slot #8 in the resource pool for the second PSFCH occasion of the PSCCH / PSSCH reception 1005. Similarly, for a PSCCH / PSSCH reception 1006 in slot #3, the UE may determine, based on the first indication, a set of PRBs 1007 in slot #8 in the resource pool for the first PSFCH occasion of the PSCCH / PSSCH reception 1006.

[0229] As above-mentioned, a resource pool may include multiple RB sets and intra-cell guard bands between every two adjacent RB sets in the frequency domain. However, one PSFCH transmission should be confined within one RB set in the frequency domain to avoid increasing the risk of potential LBT failure. Therefore, the UE needs to determine frequency resources for PSFCH transmission and reception in each RB set in the resource pool.

[0230] In the present disclosure, given the sub-channel is the minimum resource allocation granularity in the frequency domain for a PSSCH transmission or reception in a slot, it is necessary to allocate PRB(s) from the set of PRBs to a sub-channel in a slot to ensure each sub-channel within each slot could have its own dedicated PRBs allocated for PSFCH transmission. For a PSFCH occasion, the PRB allocation, from a set of PRBs corresponding to the PSFCH occasion, to a combination of a sub-channel and a slot is performed based on the number of sub-channels and the value of

[0231] In the present disclosure, for operation with shared spectrum channel access, a resource pool is (pre-) configured to include one or multiple RB sets in the frequency domain. Moreover, as in the above-mentioned first case, the resource pool includes multiple sub-channels in the frequency domain. Consequently, for the multiple subchannels in the resource pool, some sub-channels may overlap with 1 RB set, some subchannels may overlap with 1 RB set and 1 guard band, and / or, some sub-channels may overlap with 2 RB sets and 1 guard band between the 2 RB sets, and so on. As depicted in the example 800, in the frequency domain, the RB set 802 includes 50 contiguous CRBs with indexes from 2 to 51, the guard band 803 includes 6 contiguous CRBs with indexes from 52 to 57, and the RB set 804 includes 50 contiguous CRBs with indexes from 58 to 107. On the other hand, sub-channels #0, #1, #2, #3 and #4 includes 20 contiguous resource blocks in the frequency domain. To be specific, for example, the sub-channel #2 includes 20 contiguous CRBs with indexes from 42 to 61 in thefrequency domain. Therefore, in the example 800, the sub-channel #2 overlaps with 2 RB set and the guard band in the frequency domain, while other sub-channels such as sub-channel #0, sub-channel #1, sub-channel #3 and sub-channel #4 overlap with 1 RB set in the frequency domain.

[0232] As mentioned above, the specific PRB allocation to a combination of a subchannel and a slot is determined based on the number of sub-channels and the value of value ofA PSFCH transmission or reception should be performed within an RB set in frequency domain and RBs within guard band cannot be used for the PSFCH transmission or reception. However, when a resource pool includes multiple RB sets wherein a sub-channel overlaps with multiple RB sets, how to determine or allocate PRB(s) has not been specified. The present implementations of the present disclosure provide new methods and solutions on how to determine PSFCH resources for a PSFCH occasion in a resource pool for operation with shared spectrum channel access, which would provide a more efficient and flexible sidelink communication system.

[0233] In the present disclosure, determination of a PSFCH occasion may include determination of time resources for the PSFCH occasion and / or the determination of frequency resources for the PSFCH occasion. For a RX UE, determination of a PSFCH transmission occasion may include the determination of time resources for the PSFCH transmission occasion and / or the determination of frequency resources for the PSFCH transmission occasion. Likewise, for a TX UE, determination of a PSFCH reception occasion may include the determination of time resources for the PSFCH reception occasion and / or the determination of frequency resources for the PSFCH reception occasion.

[0234] Figure 11 is a diagram illustrating one implementation of a method 1100 for determination of frequency resources for PSFCH transmission and reception per RB set in a resource pool by a UE 102. In the implementation, the resource pool is (pre-)configured to include multiple RB sets in the frequency domain wherein each RB set includes a number of contiguous PRBs in the frequency domain. The number of contiguous PRBs within an RB set may be same as or different from that within another RB set. In the implementation, the above-mentioned parameter A, which is included in the SL BWP configuration, is set to “a second value” and the parameter sl- TransmissionStructureForPSFCH is not provided in the resource pool configuration.That is, the contiguous RB-based PSCCH / PSSCH transmission is applied in the resource pool. One RB-based PSFCH transmission / reception is applied in the resource pool wherein the UE may perform a PSFCH transmission / reception with HARQ-ACK information in a PRB of the resource pool. The resource pool includes NsubchannelSLsubchannels in the frequency domain wherein each sub-channel consists of Ksubcontiguous RBs in the frequency domain.

[0235] In the Figure 11, the resource pool 1101 is (pre-)conflgured to include two RB sets and one guard band between these two RB sets, i.e., the RB set 1102, the guard band 1103, and the RB set 1104 in the frequency domain. The SL resource pool 1101 in the Figure 11 is as same as the SL resource pool 801 that is specified in the Figure 8. That is, the above description in the Figure 8 can be applied to that in the Figure 11.

[0236] For a n-th PSFCH occasion where the UE may determine,based on the n-th indication provided by the above-mentioned parameter list, a set ofPRBs in the resource pool for PSFCH transmission with HARQ-ACK information. For example, as depicted in the Figure 11, the set of PRBsincludes PRBs with indexes 0, 1, 2, 12, 18, 19, 20, 28, 30, 39, 40, 41, 64, 70, 80, 92 in the resource pool.

[0237] In the implementation, for a PSFCH occasion in a PSFCH slot, the UE may perform frequency resource determination for PSFCH transmission or reception per RB set.

[0238] Within an RB set k, the UE may determine a corresponding set ofPRBs from thePRBs for PSFCH transmission within the RB set k. As depicted in the Figure 11, the UE may determine the set of PRBs within the RB set1102 (i.e., RB set k=0) where the set of PRBs includes PRBs with indexes 0,1, 2, 12, 18, 19, 20, 28, 30, 39, 40, 41. Similarly, the UE may determine the set of PRBs within the RB set 1104 (i.e., RB set k=l) where the set ofPRBs includes PRBs with indexes 64, 70, 80, 92. In other words, the UE may determine, based on the n-th indication, a set of PRBs within the RB set k in the resourcepool.

[0239] For an RB set k, the UE may determine the number of sub-channelscorresponding to the RB set k. In addition, as above-mentioned, there arePSSCH slots associated with a PSFCH slot. Therefore, there are sub-channels associated with the PSFCH slot within the RB set k. The UE may determine to allocate the PRBs to each sub-channel in each PSSCH slot among thePSSCH slots. That is, the UE may determine specific PRB(s),from the PRBs to each sub-channel in each PSSCH slot among thePSSCH slots for PSFCH transmission or reception. The UE may determineEachPRB(s) is associatedwith a sub-channel in a PSSCH slot. In other words, each PRB(s) isassociated with a sub-channel in a PSSCH slot for HARQ-ACK feedback of a PSSCH allocated in the sub-channel and in the PSSCH slot.

[0240] The specific PRB(s) allocation to each sub-channel in each PSSCH slot relies on the determined number of sub-channels for an RB set. It is crucial to accurately determine the number of sub-channels per RB set especially for the case where a subchannel may overlap with more than 1 RB set. In the present implementation, a clear and definite method of the allocation of PSFCH frequency resources to each subchannel is provided, which ensures an efficient SL communication system can be achieved. The allocation is done per RB set in the resource pool.

[0241] In an embodiment A, a determination of whether to assign a sub-channel to an RB set is performed based on whether the sub-channel overlaps with an intra-cell guard band or not. For a sub-channel overlapping with one or multiple RB sets and an intra-cell guard band in the frequency domain, the UE may determine to not assign the sub-channel to an RB set of the one or multiple overlapping RB sets.

[0242] Specifically, for a sub-channel overlapping with a single RB set and not overlapping with an intra-cell guard band, the sub-channel is determined for the overlapping RB set. For a sub-channel overlapping with a single RB set and a guard band, the sub-channel is not determined for the RB set. For a sub-channel overlapping with two RB sets and a guard band, the sub-channel is not determined for either RB set of the two overlapping RB sets. Herein, the term “a sub-channel is determined for an RB set” implies the term “a sub-channel is in an RB set”, “a sub-channel is determined to be in an RB set”, or the term “a sub-channel is determined to be one of subchannels in an RB set”. Therefore, these terms can be used interchangeably.

[0243] As depicted in the Figure 11, the UE may determine the sub-channels #0 and #1 as the sub-channels in the RB set 1102 and may not determine the sub-channel #2 to be one of sub-channels in the RB set 1102. Likewise, the UE may determine the subchannels #3 and #4 as the sub-channels in the RB set 1104 and may not determine the sub-channel #2 to be one of sub-channels in the RB set 1104. Consequently, the UE may determine that the number ofsub-channels in the RB set 1102 is 2 and the number of Asub-channels in the RB set 1104 is 2.

[0244] In other words, the UE may determine to whether count a sub-channel in the number of sub-channels for an RB set k based on whether the sub-channel includesat least one PRB that is belong to the RB set k in the frequency domain. For a subchannel in the RB set k, all PRBs of the sub-channel are included in the RB set k.

[0245] The UE may determine a number of sub-channels in an RB set kwherein, each sub-channel of the sub-channels is included in the RB set k in thefrequency domain. In other words, each sub-channel among the sub-channels doesnot overlap with one or multiple intra-cell guard bands and / or RB sets other than the RB set k.

[0246] Within the RB set k, thesub-channels can be reindexed in increasing order from 0 to — 1 from the lowest frequency location to highest frequencylocation.

[0247] Upon determining the number of sub-channels in an RB set k, the UEmay determine a number of PRBs based on the determined number of subchannels in the RB set k,and the number of PSSCH slots associated with a PSFCH slot (i.e., the period of PSFCH resources in unit of slots), The UE maydetermine the value ofis equal toThat is, for the RB set k, the value of is a result of dividing thetotal number of PRBs indicated to be used for PSFCH transmission / reception within the RB set by a product of the determined number of sub-channel in the RB set k and the number of slots.

[0248] The UE may determine to allocate every PRB(s) from thePfrfrs to a sub-channel in a slot among the PSSCH slots first in anascending order of slot index and second in an ascending order of sub-channel index.That is, each sub-channel in each slot among the PSSCH slots are associatedwith respective PRB(s). Specifically, the UE may allocate [(i + j ·PR the setBs from of PRBs to slot i among the PSSCH slots associated with the PSFCH slot andsub-channel j , where and The allocationperformed by the UE starts in an ascending order of i and continues in an ascending order of j.

[0249] As depicted in the Figure 11, slot C is an PSFCH slots andPSSCH slots (i.e., slot A and slot B) are associated with the PSFCH slot (slot C). For the RB set 1102 with index k=0, the UE may determine thatMoreover, the UE may allocate, from the set of PRBs, first 3 PRBs with indexes 0, 1 and 2 to the sub-channel #0 in the slotA, second 3 PRBs with indexes 12, 18 and 19 to the sub-channel #0 in the slot B, third 3 PRBs with indexes 20, 28 and 30 to the sub-channel #1 in the slot A, fourth 3 PRBs with indexes 39, 40 and 41 to the sub-channel #1 in the slot B.

[0250] On the other hand, for the RB set 1104 with index k=1, the UE may determine that Moreover,the UE may allocate, from the set of PRBs, the first PRB with index 64 to thesub-channel #3 in the slot A, the second PRB with index 70 to the sub-channel #3 in the slot B, the third PRB with index 80 to the sub-channel #4 in the slot A, and the fourth PRB with index 92 to the sub-channel #4 in the slot B.

[0251] According to the above embodiment, with providing specific determination of sub-channels for each RB set in a resource pool, the SL communication system ensures an exact method for determining PRB resources for a PSFCH transmission or reception that is associated with a sub-channel in a slot.

[0252] As above-mentioned, the UE may determine, for each RB set in the resource pool, a number of PRBs, that are associated with each sub-channel in aslot per RB set. The PRBs can be simply denoted as the APRBs. Based onthe configuration of bitmap provided by the parameter list, the value of thePRB(s) (i.e., the S PRBs) for an RB set may be same as or different from that for anotherRB set. That is, the value of the S PRBs determined for an RB set can be different from the value of the S PRBs determined for another RB set. How to accurately determine the PSFCH resources for a PSSCH transmission that uses multiple sub-channels overlapping with multiple RB sets in the resource pool is provided hereinafter, which ensure an efficient SL transmission system.

[0253] The UE may receive, from another UE, a PSSCH transmission in a slot in a resource pool. The resource pool consist of multiple RB sets and one or more intra-cell guard bands in frequency domain. The PSSCH transmission may be allocated with a first number of sub-channels. For convenience of illustration, the first number of continuously allocated sub-channels for the PSSCH can be denoted as sub-channels. The sub-channels may overlap with one, multiple or all of the RBsets included in the resource pool. In the implementation, the multiple RB sets overlapping with thesub-channels can be also called as the multiple overlapping RB sets hereinafter for purpose of illustration. In other words, each RB set of the multiple overlapping RB sets includes the resources (i.e., allocated sub-channels) for the PSSCH transmission.

[0254] For an RB set krthat includes resources (i.e., allocated sub-channels) for the PSSCH transmission, the UE may determine a number of sub-channels of the PSSCH transmission in the RB set k. Here, a sub-channel of the PSSCH transmission in the RB set k implies that all PRBs of a allocated sub-channel are included in the RB set k. The number of sub-channels of the PSSCH transmission in the RB set k can be denoted asFor a sub-channel, among the first number of sub-channels, that partially overlap with the RB set k (e.g., a sub-channel may overlap with the RB set k and an intra-cell guard band), the sub-channel is not included in the sub-channels. Asub-channel that partially overlaps with the RB set k implies that the sub-channel may include at least one PRB that does not belong to the RB set k.

[0255] For example, as depicted in the Figure 11, the UE may receive, from another UE, a PSSCH transmission 1105 where the PSSCH transmission 1105 uses3 sub-channels, that is, the first number of sub-channels is 3. For the PSSCH transmission 1105, RB sets that include the resources (i.e., allocated sub-channels) of the PSSCH transmission are the RB set 1102 and the RB set 1104. That is, for the PSSCH transmission 1105, there are = 1 sub-channel for RB set 1102 withindex k=0 andsub-channel for RB set 1104 with index k=1. That is, the second number of sub-channels is equal to 2. Here, given that the subchannel #2 partially overlaps with the RB set 1102, the sub-channel #2 is not included in thesub-channel in the RB set 1102. Likewise, given that the sub-channel #2 partially overlaps with the RB set 1104, the sub-channel #2 is not included in the sub-channel in the RB set 1104. That is, the sub-channel #2 is not included inthe second number of the sub-channels.

[0256] The UE may determine a second number of sub-channels for the PSSCH transmission. The second number of sub-channels includes one or more sub-channels among the first number of sub-channels wherein each of the one or more sub-channels in the second number of sub-channels is within a single RB set. That is, a sub-channel in the second number of sub-channels is within a single RB set. For a sub-channel among the first number of sub-channels, if the sub-channel partially overlaps with a RB set, the sub-channel is determined to be not included in the second number of subchannels. For a sub-channel among the first number of sub-channels, if the sub-channel fully overlaps with a RB set (i.e., the sub-channel is within a single RB set), the subchannel is determined to be included in the second number of sub-channels.

[0257] In other words, the second number of sub-channels may be determined or calculated as a summation of the over all RB sets that include the resources (i.e.,the allocated sub-channels) of the PSSCH transmission. The second number of subchannels may be determined as where the sum is over all RB-setsincluding resources (i.e., the allocated sub-channels) for the PSSCH transmission. The second number is derived by summing across RB sets that include the resources(i.e., the allocated sub-channels) of the PSSCH transmission. The sub-channelsare those sub-channels of the PSSCH transmission that are within the RB set k.

[0258] Additionally or alternatively, for a sub-channel among the subchannels of the PSSCH transmission, in a case that the sub-channel does not overlap with an intra-cell guard band, the sub-channel is determined or included in the second number of sub-channels; in a case that the sub-channel overlaps with an intra-cell guard band, the sub-channel is not determined or included in the second number of subchannels.

[0259] In other words, the second number of sub-channels may be those subchannels among the first number of sub-channels wherein each of those sub-channels is confined or included within an RB set. That is, the second number of sub-channels may not include those sub-channel(s) among the first number of sub-channels wherein the sub-channel(s) may overlap with intra-cell guard band in the frequency domain.

[0260] In the implementation,represents the first number of sub-channels allocated to the PSSCH transmission in the resource pool, while the denotes anumber of sub-channels of the PSSCH transmission that are contained in an RB set k. For an RB set k that does not include the resources (i.e., allocated sub-channels) of the PSSCH transmission, the value of the is 0. Therefore, the value of maybe equal to or larger than the value of the

[0261] In response to the reception of the PSSCH transmission, the UE may determine one or multiple PRBs in the resource pool wherein the one or multiple PRBs are the candidate PRB(s) available for the HARQ-ACK feedback of the PSSCH transmission in the resource pool. That is, the UE may select one of the one or multiple PRBs and transmit a PSFCH with the HARQ-ACK information in the selected one PRB.

[0262] In the present implementation, the UE may determine PSFCH resources for the PSSCH transmission based on the second number of the sub-channels. That is, the UE may determine PSFCH resources for the PSSCH transmission not based on the first number of the sub-channels.

[0263] For determining the PSFCH resources for the PSSCH transmission, the UE may first determine, for each RB set in the resource pool, a number ofPRB(s) (i.e., the S PRB(s)) per RB set where each PRB(s) (i.e., each SPRB(s)) in an RB set k are associated with each sub-channel in a slot for the RB set k. Each PRB(s) (i.e., each S PRB(s)) in an RB set k are available for HARQ-ACK feedback of a PSSCH in each sub-channel in each slot among the PSSCH slots.

[0264] Then the UE may determine a number of PRBs for each RB set that includes the resources for the PSSCH transmission. Here, the number of PRBs for an RB set that includes the resources for the PSSCH transmission are the candidate PRB(s) available for the HARQ-ACK feedback of the PSSCH transmission within the RB set. The number of PRBs for the RB set including the resources for the PSSCH transmission isdetermined by the UE as the number of sub-channels of the PSSCH transmission in the RB set multiplied by the number of PRBs associated with a sub-channel in a slot for the RB set. That is, for an RB set k that includes the resources for the PSSCH transmission, the number of PRBs in the RB set k is calculated aswhere theis the number of sub-channels of the PSSCH transmission that is contained in the RB set k and is the number of PRBsassociated with a sub-channel in a slot for the RB set k. ThePRBs in the RB set k that includes the resources for the PSSCH transmission are associated with the sub-channels of the PSSCH transmissionwithin the RB set k and could be determined based on the above-mentioned PRB allocation rules. For example, in the Figure 11, according to the above-mentioned PRB allocation rules, the in the RB set k= 0 are associatedwith sub-channel #1 of the PSSCH transmission within the RB set 1102 in slot A, that is, PRBs with indexes 20, 28 and 30. Similarly, theinthe RB set k= 1 is associated with sub-channel #3 of the PSSCH transmission within the RB set 1104 in slot A, that is, PRBs with index 64.

[0265] Then the UE may determine a total number of the one or multiple PRBs for the HARQ-ACK feedback of the PSSCH transmission in the resource pool by summing the number of PRBs over all the RB sets that include the resources for the PSSCH transmission. The UE may perform the calculation based onwhere the sum is over all RB-sets including resources for the corresponding PSSCH. ThePRBs are associated with thesub-channels of the PSSCH transmission and could be determined based on the above-mentioned PRB allocation rules.

[0266] For example, in the Figure 11, the total number of the one or multiple PRBs or the HARQ-ACK feedback of the PSSCH transmission in the resource pool is The one or multiple PRBs are associated withthesub-channels of the PSSCH transmission and, according to the above- mentioned PRB allocation rules, are the PRBs with indexes 20, 28, 30, and 64.

[0267] In the present disclosure, a PSFCH resource can be identified by a PRB and a cyclic shift pair. Therefore, for the PSSCH transmission, the UE may determine the number of PSFCH resources as The isequal toand theis a number of cyclic shift pairs for the resource pool provided by a parameter in the SL resource pool configuration. The PSFCH resources are first indexed according to an ascending order of the PRB index, from thePRBs, and then according to an ascending order of the cyclic shift pair index from the cyclic shift pairs. The UE may determine a PSFCH resourcefrom the PSFCH resources for the PSFCH transmission with HARQ-ACKinformation in response to the PSSCH reception based on the UE’s identity and the identity of another UE transmitting the PSSCH.

[0268] Figure 12 illustrates various components that may be utilized in a UE 1202. The UE 1202 (UE 102) described in connection with Figure 12 may be implemented in accordance with the UE 102 described in connection with Figure 1. The UE 1202 includes a processor 1281 that controls operation of the UE 1202. The processor 1281 may also be referred to as a central processing unit (CPU). Memory 1287, which may include read-only memory (ROM), random access memory (RAM), a combination of the two or any type of device that may store information, provides instructions 1283a and data 1285a to the processor 1281. A portion of the memory 1287 may also include non-volatile random access memory (NVRAM). Instructions 1283b and data 1285b may also reside in the processor 1281. Instructions 1283b and / or data 1285b loaded into the processor 1281 may also include instructions 1283a and / or data 1285a from memory 1287 that were loaded for execution or processing by the processor 1281. The instructions 1283b may be executed by the processor 1281 to implement one or more of the methods described above.

[0269] The UE 1202 may also include a housing that contains one or more transmitters 1258 and one or more receivers 1220 to allow transmission and reception of data. The transmitter(s) 1258 and receiver(s) 1220 maybe combined into one or more transceivers 1218. One or more antennas 1222a-n are attached to the housing and electrically coupled to the transceiver 1218.

[0270] The various components of the UE 1202 are coupled together by a bus system 1289, which may include a power bus, a control signal bus and a status signalbus, in addition to a data bus. However, for the sake of clarity, the various buses are illustrated in Figure 12 as the bus system 1289. The UE 1202 may also include a digital signal processor (DSP) 1291 for use in processing signals. The UE 1202 may also include a communications interface 1293 that provides user access to the functions of the UE 1202. The UE 1202 illustrated in Figure 12 is a functional block diagram rather than a listing of specific components.

[0271] Figure 13 illustrates various components that may be utilized in a base station 1360. The base station 1360 described in connection with Figure 13 may be implemented in accordance with the base station 160 described in connection with Figure 1. The base station 1360 includes aprocessor 1381 that controls operation ofthe base station 1360. The processor 1381 may also be referred to as a central processing unit (CPU). Memory 1387, which may include read-only memory (ROM), random access memory (RAM), a combination of the two or any type of device that may store information, provides instructions 1383a and data 1385a to the processor 1381. A portion of the memory 1387 may also include non-volatile random access memory (NVRAM). Instructions 1383b and data 1385b may also reside in the processor 1381. Instructions 1383b and / or data 1385b loaded into the processor 1381 may also include instructions 1383a and / or data 1385a from memory 1387 that were loaded for execution or processing by the processor 1381. The instructions 1383b may be executed by the processor 1381 to implement one or more of the methods 300 described above.

[0272] The base station 1360 may also include a housing that contains one or more transmitters 1317 and one or more receivers 1378 to allow transmission and reception of data. The transmitter(s) 1317 and receiver(s) 1378 may be combined into one or more transceivers 1376. One or more antennas 1380a- n are attached to the housing and electrically coupled to the transceiver 1376.

[0273] The various components of the base station 1360 are coupled together by a bus system 1389, which may include a power bus, a control signal bus and a status signal bus, in addition to a data bus. However, for the sake of clarity, the various buses are illustrated in Figure 13 as the bus system 1389. The base station 1360 may also include a digital signal processor (DSP) 1391 for use in processing signals. The base station 1360 may also include a communications interface 1393 that provides user access to the functions of the base station 1360. The base station 1360 illustrated in Figure 13 is a functional block diagram rather than a listing of specific components.

[0274] The term “computer-readable medium” refers to any available medium that can be accessed by a computer or a processor. The term “computer-readable medium,” as used herein, may denote a computer- and / or processor-readable medium that is non- transitory and tangible. By way of example, and not limitation, a computer-readable or processor-readable medium may comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer or processor. Disk and disc, as used herein, includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray® disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers.

[0275] It should be noted that one or more of the methods described herein may be implemented in and / or performed using hardware. For example, one or more of the methods described herein may be implemented in and / or realized using circuitry, a chipset, an application-specific integrated circuit (ASIC), a large-scale integrated circuit (LSI) or integrated circuit, etc.

[0276] Each of the methods disclosed herein comprises one or more steps or actions for achieving the described method. The method steps and / or actions may be interchanged with one another and / or combined into a single step without departing from the scope of the claims. In other words, unless a specific order of steps or actions is required for proper operation of the method that is being described, the order and / or use of specific steps and / or actions may be modified without departing from the scope of the claims.

[0277] It is to be understood that the claims are not limited to the precise configuration and components illustrated above. Various modifications, changes and variations may be made in the arrangement, operation and details of the systems, methods and apparatus described herein without departing from the scope of the claims.

Claims

[CLAIMS]1. A user equipment (UE), comprising: reception circuitry configured to receive a PSSCH in a SL resource pool, the SL resource pool consisting of multiple RB sets and one or more intracell guard bands in frequency domain, and the PSSCH been allocated with a first number, N, of sub-channels; and control circuitry configured to determine Physical Sidelink Feedback Channel (PSFCH) resources for the PSSCH based on a second number, M, of sub-channels, wherein the M sub-channels are selected from the A subchannels, and wherein all Physical Resource Blocks (PRBs) of each of the M sub-channels are contained within a single RB set.

2. The UE of claim 1 , wherein: for a sub-channel among the N sub-channels, in a case that all PRBs of the sub-channel is contained within a single RB set, the sub-channel is determined to be included in the M sub-channels, and in a case that the sub-channel partial overlaps with a single RB set, the sub-channel is determined not to be included in the M sub-channels.

3. The UE of claim 1, wherein: an RB set includes a first number of contiguous PRBs in frequency domain, and a sub-channel includes a second number of contiguous PRBs in frequency domain.

4. A communication method performed by a user equipment (UE), comprising: receiving a PSSCH in a SL resource pool, the SL resource pool consisting of multiple RB sets and one or more intra-cell guard bands in frequency domain, and the PSSCH been allocated with a first number, N, of subchannels; and determining Physical Sidelink Feedback Channel (PSFCH) resources for the PSSCH based on a second number, M, of sub-channels, wherein the M sub-channels are selected from the N sub-channels, and wherein allPhysical Resource Blocks (PRBs) of each of the M sub-channels are contained within a single RB set.

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